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Lumber Glossary



Abney Level Hand-held clinometers that are used to measure slope in percent.
Above-ground Biomass The above ground portion of a tree, excluding the root system.
Abrasives A material that is used to shape or finish a work piece through rubbing which leads to the work piece being worn away.
Absolute Humidity The weight of water vapor per unit of air; usually expressed as grains/cu. ft.
Absorption The gain of free water by the cell cavities.
Access The means of gaining entry to timber on a tract or logging chance.
Accumulating Sheer Shearhead on a feller-buncher that is capable of accumulating and holding two or more cut stems.
Across The Grain Generally perpendicular to the grain direction.
Actual Dimensions The exact measurements of a piece of lumber. (i.e. – a 2×4 (nominal dimensions) is actually 1 ½ inches thick by 3 ½ inches wide.)
AD (Air-Dried) Lumber which has been air dried.
ADF A term used to define a condition upon which payment of an invoice may be made.
Adherent A material that is held to another material by an adhesive.
Adhesion A substance in which two surfaces are held together by inter-facial forces, which may consist of valence forces or interlocking action or both.
Adhesive A substance capable of bonding material together by surface attachment.
ADI After date of Invoice.
Admiralty Shackle A heavy shackle at the tail end of the tree that connects the skyline to the sub line (guy line extension).
Adult Wood Wood produced after cambial cells have attained maximum dimensions.
Advanced Decay An older stage of decay readily recognized as wood that has become punky, soft, spongy, stringy, rinkshaked, pitted, or crumbly.
Adverse Grade In highway transport, uphill haul that requires trucks to use lower gears; a gradient that slopes upward in the direction of loaded log truck travel.
Aerial Logging Yarding system employing aerial lift of logs, such as balloons or helicopters.
Afforestation Establishment of forest crops through artificial methods, such as planting or sowing on land where trees have never grown.
A-Frame Two wooden or metal uprights mounted in the shape of the letter “A” to support lead blocks at the upper end.
African Blackwood Dark purple-brown with black streaks
African Mahogany Heartwood varies from light to deep reddish-brown
African Padauk Vivid blood red heartwood to dark purple-brown
African Walnut Bronze-Orange heartwood
After Date of Invoice A term used to define a condition of sale; cash discounts are often allowed for payment within a specified period “after date of invoice.”
After Deducting Freight A term used to define a condition upon with payment of an invoice may be made.
Against The Grain A reference to the cutting direction; as in planing a board surface, such that splitting ahead of the cutter follows the grain direction downward into the wood below the projected cutting surface. Also, generally perpendicular to the grain direction, across the grain.
Age Mean age of the trees comprising a crop, forest, or stand. In forests, the mean age of dominant (and sometimes co-dominant) trees is taken. The plantation age is generally taken from the year the plantation was begun without adding the age of the nursery stock.
Age Class One of the intervals, commonly 10 or 20 years, into which the age range of tree crops is divided for classification or use. Also pertains to the trees included in such an interval. (i.e. trees ranging in age from 21 to 40 years fall into a 30-year ago class; 30 designates the midpoint of the 20-year interval from 21 to 40 years.)
Air Cleaner (Air Polisher) A machine designed to filter fine dust from the air in a workshop. A blower moves air past a series of filters to capture the airborne dust.
Air Compressor A compressor that takes in air at atmospheric pressure and delivers it as a higher pressure.
Air Hose A hose that carries air under pressure.
Air-Dried Lumber Lumber that was dried, usually outside, to equilibrium moisture content with the air it was exposed to. Any lumber below 30% MC is classified as air dried. Construction grade is around 19% MC. Moisture content of air-dried wood fiber depends on length of drying period, relative humidity, and temperature. It’s also referred to as air seasoned.
Air-dried lumber. Lumber that has been piled in yards or sheds for any length of time. For the United States as a whole, the minimum moisture content of thoroughly air dried lumber is 12 to 15 percent and the average is somewhat higher. In the South, air dried lumber may be no lower than 19 percent.
Airway. A space between roof insulation and roof boards for movement of air.
Alder Dull reddish brown with darker lines
All Widths and Lengths A term used indicating that all widths and lengths of a specified thickness of lumber may be included in a shipment.
All-Aged Forest or stand containing trees of almost all age classes up to and including trees of harvestable age.
Allen Head A screw head with a recess requiring a hexagon shaped key, used mainly on machinery. These may be in metric or SAE sizes.
Alligatoring. Coarse checking pattern characterized by a slipping of the new paint coating over the old coating to the extent that the old coating can be seen through the fissures.
Allowable Cut Volume of timber that may be harvested during a given period of time to maintain sustained production.
Allowable Property The value of a property normally published for design used. Allowable properties are identified with grade descriptions and standards, reflect the orthotropic structure of wood, and anticipate certain end uses.
Allowable-Cut Effect (A.C.E) Allocation of anticipated future forest timber yields to the present allowable cut; this is employed to increase current harvest levels, especially when constrained by even flow by spreading anticipated future growth over all the years in the rotation.
Along the Grain Generally paralleled to the grain direction.
Alternate An alternating set of teeth on a saw blade with a left-right sequence.
Alternate Top Bevel with Raker (ATB/R) A design for a circular saw blade where four alternately beveled teeth are followed by a raker tooth to remove debris from the cut.
Ambrosia Maple The ambrosia beetle causes the wormy pattern in this soft maple
American Lumber Standard The American Softwood Lumber Standards establishes standard sizes and requirements for the development and coordination of lumber grades of various species, the assignment of design values when called for, and the preparation of grading rules applicable to each species.
American Tree Farm System (ATFS) A program of the American Forest Foundations Center for Family Forests is the oldest of forest certification programs and was established in 1941. The ATFS focuses its program on private family forest landowners in the United States.
Anchor Piece of equipment that holds something in place. i.e. – a clamp is a type of anchor.
Anchor bolts. Bolts to secure a wooden sill plate to concrete , or masonry floor or wall.
Anchor Cable A line used to tie down a yarded to prevent tipping on heavy pull.
Anchor Log Concrete, metal or wooden bars buried in the earth to hold a guy rope. This is also called a deadman.
Andiroba Light mahogany color to reddish-brown
Aniegre Heartwood is cream colored to tan with a pinkish tinge
Anisotropic Shows different properties when measured along a different axes.
Annual Allowable Harvest Quantity of timber scheduled to be removed from a particular management unit in one year.
Annual Growth Rings The layer of growth that a tree puts on in one year. The annual growth rings can be seen in the end grain of lumber.
Applied Carving A background which is worked separately and then applied, rather than being worked in place.
Apron A frame around the base of a table to which the top and legs are fastened.
Apron. The flat member of the inside trim of a window placed against the wall immediately beneath the stool.
Arbor A shaft, driven by the tools motor that turns blades or other cutting tools.
Arch Supporting device mounted on or towed behind or a skidding vehicle. This is used to lift one end of a log(s) to reduce sliding resistance and/or transfer the weight.
Area Regulation Method of controlling the annual or periodic acreage harvested from a forest, despite fluctuations in fiber-yield volumes. This leads to a managed forest.
Area Salvage Timber sales in which the USDA Forest Service sells dead timber within a given area. Usually covers more than an operating season and requires the operator to return annually to remove any dead timber present.
Areaway. An open subsurface space adjacent to a building used to admit light or air or as a means of access to a basement.
Ash Grey-brown heartwood
Asphalt. Most native asphalt is a residue from evaporated petroleum. It is insoluble in water but soluble in gave. line when heated. Used widely in building for waterproofing roof coverings of many types, exterior wall coverings, flooring tile, and the like.
Assembly Time The time elapsed between spreading adhesive on surfaces to be joined and application of pressure to the joint. Open assembly time is from the beginning of spreading to joint closure. Closed assembly time is from joint closure to application of full pressure.
Association of American Railroads (AAR) A trade association based in Washington, D.C. representing the nations Class I Railroads. The AAR represents the industry in the broad fields of Law, Public Affairs, Legislation, Economics and Finance, Research and Testing, Transportation, Safety, Engineering, Freight Claim and Prevention and Car service.
Astragal. A molding, attached to one of a pair of swinging doors, against which the other door strikes.
Attached Deck A deck with one or more sides supported by a ledger and attached to a house.
Attic ventilators. In houses, screened opening) provided to ventilate an attic space. They are located in the soflit area as inlet ventilators and in the gable end or along the ridge as outlet ventilators. They can also consist of power-driven fans used as an exhaust system. (See also Louver.)
Auger Various hand tools, typically that have a threaded shank and cross handle, used for boring holes in ice or wood.
Australian Cypress Mostly golden colored
AW&L A term used indicating that “all widths and lengths” of a specified thickness of lumber may be included in a shipment.
Awl A pointed instrument that looks like an ice pick, useful for marking positions when laying out a project.
AWLS A term used indicating that all widths and lengths of a specified thickness of lumber may be included in a shipment.



B&S Beams and Stringers
B/L Bill of Lading – A written document issued by a carrier serving as a receipt of goods and as a contract to deliver goods to a specified destination.
Back Saw A short rectangular saw with fine teeth and a rigid “spine” along the top of the blade. A back saw is used for fine joinery work such as cutting dovetail joints.
Backcut The final cut in felling a tree, made on the opposite side of the direction of fall.
Backfill. The replacement of excavated earth into a trench around and against a basement foundation.
Backfire A blaze set in front of an advancing forest fire in an effort to check the wildfire by cutting off its fuel supply.
Backhand. A simple molding sometimes used around the outer edge of plain rectangular casing as a decorative feature.
Balanced Construction The symmetrical construction of plywood or other composites having matching layers on both sides of the central plane so that changes in moisture content will not cause warp.
Baluster One of a series of vertical supports used between posts of a railing. This is also called a spindle.
Balusters. Usually small vertical members in a railing used between a top rail and the stair treads or a bottom rail.
Balustrade. A railing made up of balusters, top rail, and sometimes bottom rail, used on the edge of stairs, teal conies, and porches.
Band Saw A saw with a looped blade running around two or three wheels. This is used with narrow blades for cutting freehand shapes, or with wider blades and a guide for re-sawing material.
Band Strength The ability of saw blade to resist deflection determined by width & thickness (AKA beam strength).
Bare Root seedling; tree seedling grown in a nursery bed. When large enough for transplanting, the seedling is lifted from the nursery bed, and the dirt is removed from the roots before packaging.
Barge board. A decorative board covering the projecting rafter (fly rafter) of the gable end. At the cornice, this member is a facie board.
Bark The outermost, protective layer of a tree composed of dead cork and other various elements.
Bark Beetle Small, cylindrical beetle of the family Scolytidae, the adult of which bores into and beneath the bark of various trees for the purpose of egg laying.
Bark Pocket An opening between annual growth rings that contains bark. Bark pockets appear as dark streaks on radial surfaces and as rounded areas on tangential surfaces.
Bark Residue Refers to the bark removed from a log and also to portions of wood and foreign matter such a grit, sand, or stones that may be imbedded in the bark.
Barker A machine used to remove bark from pulpwood.
Barking Drum A large drum in which logs or billets are tumbled by mechanical rotation, the back being removed by abrasive action.
Barking Iron A tool with a curved, narrow-shaped blade used in removing bark by hand.
Basal Area Cross sectional area of a tree, in square feet, measured at breast height. This is used as a method of measuring the volume of timber in a given stand.
Base molding. Molding used to trim the upper edge of interior baseboard.
Base or baseboard. A board placed against the wall around a room next to the floor to finish properly between floor and plaster.
Base shoe. Molding used next to the floor on interior base board. Sometimes called a carpet strip.
Basswood Creamy white to pale pink color
Bastard Grain Annual rings on an angle at or near 45 degrees to the wide face of a piece of lumber.
Bastard Sawn Lumber in which the annual rings make angles of 30 to 60 degrees with the surface of the piece.
Batten. Narrow strips of wood used to cover joints or as decorative vertical members over plywood or wide boards.
Batter board. One of a pair of horizontal boards nailed to posts set at the corners of an excavation, used to indicate the desired level, also as a fastening for stretched strings to indicate outlines of foundation walls.
Bay The space between two timber bents.
Bay window. Any window space projecting outward from the walls of a building, either square or polygonal in plan.
BD Board
BDFT Board foot
BDL Bundle
Bead A semicircular piece of molding.
Beam A main horizontal member in a buildings frame. Beams usually are supported by posts.
Beam. A structural member transversely supporting a load.
Beams and Stringers Large pieces (nominal dimensions, 5” and thicker, width more than 2” greater than thickness) of rectangular cross section graded with respect to their strength in bending when loaded on the narrow face.
Bearing partition. A partition that supports any vertical load in addition to its own weight.
Bearing wall. A wall that supports any vertical load in addition to its own weight.
Bed molding. A molding in an angle, as between the over hanging cornice, or eaves, of a building and the side walls.
Beech Reddish-brown
Beetle A heavy wooden mallet or maul used when material would be damaged by a sledge hammer.
Belt Sander A machine used to sand down wood or other materials for finishing purposes. It has an electrical motor that turns a pair of drums on which a seamless loop of sand paper is mounted; it can be handheld or stationary.
Bench Dog A metal part of a wooden peg that fits into a hole in a workbench that is used to hold a work piece in place. The peg can be round or square and sometimes is fitted with special springs to hold them in place.
Beneficiation A process used to upgrade chips, making them more acceptable for paper and pulp manufacture. Beneficiation is accomplished when acceptable chips are separated from unacceptable ship.
Bent A structural section of a frame which is composed of a line of vertical posts and the horizontal timbers that connect them.
Bent Design The artistic, yet functional pattern of timbers creating the bend.
Better A term usually used to indicate that a lumber shipment contains a percentage of pieces that are of a higher grade than the lowest grade stated. (i.e. No. 2 & BTR would contain pieces of No. 2 grade and some that are of a higher grade.)
BEV Bevel
Bevel Cut An angled cut through a board.
Bevel Gauge Also known as a T-bevel, the bevel gauge is a flat piece of metal attached to a handle with a wing nut that allows the metal piece to be set at any angle to the handle. Its used primarily to mark angles when copying them from a plan or piece of the deck to another piece.
BH Boxed Heart
Bi-metal Blade Band saw blade composed of two types of welded alloy steel.
Bind To get a saw stuck when bucking or felling a tree and the sides of the cut pinch in; wedges are used to alleviate the situation.
Binder Chain or wire rope used to bind logs. This is also known as a chain hook.
Biomass Total woody material in a forest. This refers to both merchantable material and material left following a conventional logging operation.
Biomass Harvesting Harvesting of all material including limbs, tops, and unmerchantable stem and stumps, usually for energy wood.
Birch Yellow sapwood
Birds-Eye Figure A figure composed of many small “BB” size rounded areas, resembling a bird’s eye. The figuring is most common on plain and rotary sawn lumber and is generally found on maple, along with a few other species.
Biscuit Joint A butt joint that is reinforced with a football shaped “biscuit”. The biscuits are usually made from compressed pieces of wood, most commonly birch. When a biscuit comes in contact with glue in the joint, it swells creating a tighter joint.
Blade Stabilizers Metal disks approximately 3 ½” in diameter that go on each side of a saw blade to minimize flexing and rim vibrations.
Blemish A defect or anything that marks the appearance of wood.
Blind stop. A rectangular molding, usually ¾ ¾by 1-3/8 inches or more in width, used in the assembly of a window frame. Serves as a stop for storm and screen or combination windows and to resist air infiltration.
Blind-nailing. Nailing in such a way that the nailheads are not visible on the face of the work—usually at the tongue of matched boards.
Blister An elevation of the surface of an adherent, somewhat resembling in shape a blister on human skin.
Block Plane A small plane used to finish off rough edges of a deck.
Bloodwood Heartwood varies from gray-red to deep rich red
Bloom Crystals formed on the surface of treated wood by exudation and evaporation of the solvent in preservative solutions.
Blow Usually in plywood and particleboard, the development of steam pockets during hot pressing of the panel, resulting in an internal separation or rupture when pressure is released.
Blue Board A weather resistant, plaster-based drywell.
Blue stain. A bluish or grayish discoloration of the sapwood caused the growth of certain mold like fungi on the surface and in the interior of a piece, made possible by the same conditions that favor the growth of other fungi.
Blue-Stain Discoloration in the sapwood of pine. At one time, this was thought to be a serious defect but now it is used as high-quality interior finish.
Blue-Stain Fungus The most common form of fungal stain occurring in sapwood. Conifers are most susceptible but it may also occur in light-colored heartwood other or perishable timbers. It commonly develops in dead trees, logs, lumber, and other wood products until the wood is dry. It also reduces the grade of wood, but does not significantly reduce the strength. Some blue-stain lumber is highly valued for specialty products.
BM Board Measure
Board Foot The basic unit of measurement for lumber. (i.e. – One board foot is equal to a 1-inch board, 12 inches in width and 1 foot in length. A 10-foot long, 12-inch wide and 1-inch thick piece would contain 10 board feet. When calculating board feet, nominal sizes are assumed.)
Board Measure Is used to indicate that a ‘board foot’ is the unit of measure.
Boards Lumber two-inches or more wide that is nominally less than two-inches thick. Boards less than six-inches wide are also called strips.
Bodied linseed oil. Linseed oil that has been thickened in viscosity by suitable processing with heat or chemicals. Bodied oils are obtainable in a great range in viscosity from a little greater than that of raw oil to just short of ajellied condition.
Boiled linseed oil. Linseed oil in which enough lead, manganese or cobalt salts have been incorporated to make the oil harden more rapidly when spread in thin coatings.
Bole A tree stem that has roughly grown to a substantial thickness; capable of yielding large poles, saw timber, or veneer logs.
Bolster. A short horizontal timber or steel beam on top of a column to support and decrease the span of beams or girders.
Bolt A short section of a tree mark.
Bond The union of materials by adhesives.
Bond Failure Rupture of adhesive bond.
Bond Strength The unit load applied in tension, compression, flexure, peel impact, cleavage, and/or shear required to break an adhesive assembly, with failure occurring in or near the plane of the bond.
Bondline The layer of adhesive that attaches two adherents.
Bone-Dry Ton Wood pulp or residue that weigh 2,000 pounds at zero percent moisture content. This is also known as an over-dry ton.
Bookmatch A term in sawing or veneering, where successive pieces of boards or veneer, from a flitch or a log, are arranged side by side. A properly done bookmatch will resemble a mirror image of the opposite side. Also known as butterflied, mirrors, and sisters.
Bore A hole for the arbor in a circular saw blade.
Boston ridge. A method of applying asphalt or wood shingles at the ridge or at the hips of a roof as a finish.
Bottom Rail The horizontal member, installed on edge, attached to the bottom of the balusters, as well as the post. The bottom rail is not required if the balusters extend to and are attached to the Rim Joist.
Boule A log live sawn and kept together in the order of sawing.
Bound Water Water found within the cell wall of wood.
Bow A defective piece of lumber that has warped along its length.
Box Beam A built-up beam with solid wood flanges and plywood or wood-based panel product webs.
Box Heart The term used when the pith falls entirely within the four faces of a piece of wood anywhere in its length.
Box Joint A corner joint made up of interlocking “fingers”.
Box Lumber Factory lumber, may be of any thickness, 4/4 and thicker and is graded for box cutting value.
Box Shook Produced by resawing standard S2S lumber; is cut to size for box manufacture but not yet assembled may be manufactured in many sizes to meet each individual buyer’s requirements.
Boxed Heart Used when the pith falls entirely within the four faces anywhere in the length of a piece.
Brace and Bit A hand drill with a crank shaped handle with a flat knob on the end, special auger bits with a square tapered shank fit into a two jaw chuck. This is an ancient system but still works well for jobs done by hand.
Brace. An inclined piece of framing lumber applied to wall or floor to stifled the structure. Often used on walls as temporary bracing until framing has been completed.
Braces Smaller timbers placed diagonally between posts and girts (plates) to make a structure more rigid.
Bracing Structural supports placed between posts and beams or joists to provide stability to the structure.
Brad A small finishing nail up to 1” long.
Brad Point Bit Similar to a twist drill but with a flat bottom and sharp point.
Brand A log mark used to identify logs.
Branding Ax An ax used to stamp brands into logs.
Branding Iron A tool used for burning a logo or name on to wood; electric or flame heated.
Brashness Brittleness in wood, characterized by abrupt failure rather than splintering. Causes include reaction wood, juvenile wood, compression failure, high temperature, and extremes of growth rate.
Brazilian Cherry Heartwood is salmon red to orange-brown with dark brown streaks
Break A piece of equipment that bends metal sheeting into perfect angles.
Breaking Radius The limiting radius of curvature to which wood or plywood can be bent without breaking.
Brick veneer. A facing of brick laid against and fastened to sheathing of a frame wall or tile wall construction.
Bridging Boards placed perpendicularly between joists to stiffen the joists. Frequently, bridging is made from the same dimensions lumber as the joists.
Bridging. Small wood or metal members that are inserted in a diagonal position between the floor joists at midspan to act both as tension and compression members for the purpose of bracing the joists a spreading the action of loads.
Bright Term used to indicate that lumber is free from discoloration.
Bright Sapwood/No Defect Bright sapwood that is permitted in each piece of any amount.
BSND Bright Sapwood No Defect
BTR Better
Bubinga Medium red-brown color
Buck. Often used in reference to rough frame opening members. Door bucks used in reference to metal door frame.
Buglehead Screw A screw with a curved taper between the head and shank or threads so it doesn’t tear the wood when screwed down flush with the surface.
Building Code A set of regulations governing construction in a particular political subdivision, such as a city or county. The building code spells out requirements pertaining to such criteria as grades, lumber strength, spans and values.
Built-up roof. A roofing composed of three to five layers of asphalt felt laminated with coal tar, pitch, or asphalt. The top is finished with crushed slag or gravel. Generally used on flat or low-pitched roofs.
Built-Up Timbers An assembly made by joining layers of lumber together with mechanical fastening so that the grain of all laminations is essentially parallel.
Bullnose The process of rounding an edge of a board used for seating, shelving, stadium seating steps, etc.
Burl Bulges and irregular growths that form on the trunks and roots of trees. Burls are highly sought after for the incredible veneer they yield.
Burr A raised ridge of metal used on a scraper to remove wood.
Butt Diameter The larger cross-sectional measurement of a log, at the end toward the original base of the tree.
Butt Joint A woodworking joint where the edges of two boards are placed against each other.
Butt joint. The junction where the ends of two timbers or other members meet in a square-cut joint.
Butternut Medium dark brown heartwood
Buttress A ridge of wood developed in the angle between a lateral root and the butt of a tree, which may be extended up the stem to a considerable height.


C&F Cost and Freight
Caliper Instrument for determining log and tree diameters by measuring their rectangular projection on a straight graduated rule via two arms, one of them sliding along at right angles to the rule itself. The optical caliper determines upper, out-of-reach diameters through an optical system incorporating two parallel lines of sight separated by a variable baseline.
Cambium The live, actively growing layer of a tree. The cambium is one cell thick and resides between the phloem and sapwood. It repeatedly divides itself to form new wood which causes the tree to expand and grow. It is the layer that becomes either bark or wood and lays dormant during winter.
Canadian Standards Association (CSA) A non-profit organization that has developed over 2,000 different standards for a variety of industries.
Canary Heartwood varies from pale-yellow-brown to pale olive-brown streaks
Canopy A continuous cover of branches and foliage formed collectively by adjacent tree crowns.
Cant A log that has been debarked and sawn square.
Cant strip. A triangular shaped piece of lumber used at the junction of a flat deck and a wall to prevent cracking of the roofing which is applied over it.
Cantilever The allowable overhang past the joists or rim joists.
Cap Rail The top horizontal piece of a railing placed to give it a finished appearance.
Cap. The upper member of a column, pilaster, door cornice, molding, and the like.
Carbide Tipped Extremely hard steel pieces with sharp cutting edges fastened to cutting tools such as saw blades, and router bits.
Carcase The body of a piece of furniture with a box like shape.
Card Scraper A flat blade with a burred edge used for smoothing.
Carload A railroad car loaded to meet railed minimum weight requirements for carload rates. The volume in a carload may vary, depending upon the type of lumber loaded and the size of the car.
Carpenter’s Pencil Rectangular shaped pencil, about 1/4”x ½”, with a 1/16” x 3/16” lead.
Carriage Bolt A bolt with a rounded head that is pulled down onto the surface of the wood as the nut is tightened. It’s used to hold structural members together, as the rounded head gives a finished look to the bolt. Bolts should be checked annually and tightened when necessary.
Case Hardening A defect in lumber caused when a board is dried too fast, or improperly. The outer layers in a case hardened board are compressed while the inner layers are in tension.
Casement frames and sash. Frames of wood or metal enclosing part or all of the sash, which may be opened by means of hinges affixed to the vertical edges.
Casing Usually run to pattern and is widely used for interior trim.
Casing. Molding of various widths and thicknesses used to trim door and window openings at the jambs.
Cat’s Paw A person used by another as a dupe or a tool.
Catalyst A substance that initiates or changes the rate of chemical reaction but is not consumed or changed by the reaction.
Caul Veneering A method where the veneers are cut square, taped together and laid as a single sheet without preliminary dampening.
Caulking Seam A machined groove or depression worked in the wood. It provides a weather resistant joint when filled with caulking material and fitted with an adjoining piece.
CB Center Beaded
Cedar Any spreading evergreen conifer of the genus Cedrus bears tufts of small cones and needles. In full cedar wood, the fragrant durable wood of any cedar tree. Cedar lumber provides one of the best choices for deck construction, although more expensive than the cheaper options, it will last much longer because of its natural decay resistant and insect repellant properties.
Ceiling A lumber pattern featuring a center and edge V and/or bead.
Cell The smallest, microscopic structure in wood.
Cellulose The carbohydrate that is the principal constituent of wood and forms the framework of the wood cells.
Cement A powder that serves as a binding element in concrete and mortar. Also, it is an adhesive.
Cement, Keene’s. A white finish plaster that produces an extremely durable wall. Because of its density, it excels for use in bathrooms and kitchens and is alsoused extensively for the finish coat in auditoriums, public buildings, and other places where walls may be subjected to unusually hard wear or abuse.
Center Beaded A patterned lumber shaped to form a narrow half-circle along the center of its length.
Center Match (CM) Lumber that has been worked with a tongue exactly in the center on one edge of each piece and a groove on the opposite edge to provide a close tongue-and-groove joint by fitting two pieces together.
Center V (CV) Patterned lumber shaped to form an angled groove along the center of its length.
Center-to-Center Spacing The spacing between structural members determined by measuring from the center of one to the center of the next. (i.e. 16-inches o.c.)
Chain Saw A saw that is powered by an electric motor, gasoline, or hydraulics; cutting elements are on an endless chain similar to a bicycle chain.
Chalk Line An enclosed reel of string coated with colored chalk and used to mark straight lines by pulling the string taut and snapping the string, leaving a line of chalk marking a line. Commonly used in deck building to mark the edge of decking so that all decking boards can be cut off flush with each other.
Chamfer A bevel or slope created by slicing off the square edge or end of a piece of wood or other material (usually 45 degrees); a decorative edging or relief made at the timber’s corner.
Check A lumber defect caused by uneven shrinking of the wood during drying. A checked board has splits that develop lengthwise across the growth rings.
Check Scaler A person who rescales logs in order to detect errors in the initial scaling.
Checking. Fissures that appear with age in many exterior paint coatings, at first superficial, but which in time may penetrate entirely through the coating.
Checkrails. Meeting rails sufficiently thicker than a window to fill the opening between the top and bottom sash made by the parting stop in the frame of double~hung windows. They are usually beveled.
Chemical Pulping A process in which wood fibers are separated by removing the lignin and other wood components through the use of chemicals.
Chemical Thinning Any thinning in which the unwanted trees are killed by chemical poisoning; band or frill girdling may be done at the same time.
Cherry Heartwood varies from rich red to reddish-brown
Chip A small piece of wood used to make pulp. Chips are made either from wood waste in a sawmill, pulpwood operation, or from pulpwood specifically cut for this purpose.
Chipboard A paperboard used for many purposes that may or may not have specifications for strength, color, or other characteristics. It is normally made from paper stock with a relatively low density.
Chip-n-Saw A registered trade name for a machine that makes small logs into cants, converting part of the outside of the log directly into chips without producing any sawdust. Cants are then sawn into lumber as part of the same operation.
Chipped Grain A machining defect in which small chips are torn from the surface below the intended plane of cut, usually as the result of cutting against the grain.
Chisel A metal tool with a sharp beveled edge, used to cut and shape metal, stone, or wood.
Chop Saw (Miter Saw) A hollow-ground saw in diameters from 6 to 16 inches, used for cutting off and mitering on light stock such as moldings and cabinet work.
Chord The bottom or top member of a truss to which the web members are attached.
Chuck An attachment to hold work or a tool in a machine; lathe chucks and drill chucks are examples.
CIF Cost, Insurance, and Freight
CIFE Cost, Insurance, Freight, and Exchange
Circular Saw A power saw that has a steel disk with cutting teeth on the periphery; rotates on a spindle.
Cladding The application of one material (metal, wood, vinyl) over another to provide a protective layer against rain, and other weather elements. Cladding is designed to prevent water from infiltrating the structure and is not “waterproof.” It is also chosen for architectual design.
Clamp A fastening device to hold or secure objects tightly together to prevent movement or separation through the application of inward pressure.
Clear (CLR) A board which is free from defects. A term including the higher grades of lumber sound, relatively free of blemishes.
Clear-Cut Cutting all trees in an area to a minimum diameter, such as 4 inches.
Cleavage In an adhesively bonded joint, a separation in the joint caused by a wedge or other crack-opening type action.
Clevis “U”-shaped metal fitting, with a pin connecting the two ends, used for connecting cables and rigging the “C” shaped hook with a pin through it for use in attaching or towing a cable.
CLF Hundred Lineal Feet
CLG Ceiling
CLIB California Lumber Inspection Bureau
Climax Species Plant species that remains essentially unchanged in terms of species composition for as long as the site remains undisturbed.
Clinometer A hand instrument used by foresters and timber cruisers to measure vertical angles. Such angles, when correlated with specific distances, indicate the height of standing trees.
Close Grain Wood with narrow and inconspicuous annual rings; the term is sometimes used to designate wood having small and closely spaced pores, but in this sense, the term “fine textured” is more often used; wood with more than six rings per inch
Closed Coat A piece of sandpaper whose surface is completely covered with abrasive particles. This type of paper tends to clog easily with sawdust and is not popularly used for woodworking.
Coarse-Grained Wood with wide and conspicuous annual rings; rings in which there is considerable difference between springwood and summerwood; used to designate wood with large pores.
Cock Bead Any bead which stands raised from the surface as distinct from flush or sunk; usually taken to apply to small beads or edgings to drawer fronts and cupboard doors.
Cocobolo Very heavy, tough, strong timber
Codes Regulations detailing accepted materials and methods of building. Usually codes are adopted by city, county, or state building departments. Most counties promulgate local building codes.
Cohesion The state in which the constituents of a mass of material are held together by chemical and physical forces.
Cold Pressing A bonding operation in which an assembly is subjected to pressure without the application of heat.
Collapse The flattening of single cells or a row of cells in hardwood during the drying or pressure treatment of wood characterized externally by a caved-in or corrugated appearance.
Collar beam. Nominal 1- or 2-inch-thick members connecting opposite roof rafters. They serve to stiffen the roof structure.
Collar Tie A timber placed horizontally and between rafters that control sagging or spreading of the rafters; usually placed parallel to the grits which connect rafter pairs at a given height.
Collet In a router, the sleeve that grips the shank of a bit.
Colonial Siding AKA “Bevel Siding” is exterior cladding used for weather protection and architectural design.
Column A structural member, usually subject to longitudinal compression.
Column. In architecture: A perpendicular supporting member, circular or rectangular in section, usually consisting of a base, shaft, and capital. In engineering: A vertical structural compression member which supports loads acting in the direction of its longitudinal axis.
Combination doors or windows. Combination doors or windows used over regular openings. They provide winter insulation and summer protection and often have self storing or removable glass and screen inserts. This eliminates the need for handling a different unit each season.
Combination Square A square that measures both 45 degree and 90 degree angles.
Come Along A hand operated ratching wrench. It uses include tightening joinery during assembly, as a safety tie and for pulling frame components together during erection.
Commission Man A middleman who arranges sales for a commission but does not take title to the lumber.
Common Grade Lumber Lumber with obvious defects.
Common Rafters Closely and regularly spaced incline timbers that support the roof covering; independent of the bent system.
Commons Ordinary grades of knotty lumber.
Compass An instrument for drawing circles consisting of two legs joined at a pivot hinge.
Composite Assembly A combination of two or more materials bonded together that perform a single unit.
Composite Decking Deck boards manufactured from wood fiber and plastic. It is sold as an alternative to wood decking. There are various composite decking manufacturers with varied degrees of quality which can lead to low product quality.
Compound Curvature Wood bent to a compound curvature, no element of which is a straight line.
Compound Cut An angled cut to both the edge and face of a board.
Compound Miter An angled cut to both the edge and face of a board; most common use is with crown molding.
Compreg Wood in which the cell walls have been impregnated with synthetic resin and compressed to give it reduced swelling and shrinking characteristics and increased density and strength properties.
Compression Failure Deformation of the wood fibers resulting from excessive compression along the grain either in direct end compression or in bending.
Compression Wood Abnormal wood that often forms on the lower side of branches and of leaning trucks of softwood trees; compression wood is identified by its relatively wide annual rings, usually eccentric, and its large amounts of summerwood, usually more than 50% of the width of the annual rings.
Concave An inward-curving shape.
Concentrated Load The application of a relatively large force on a relatively small area.
Concentration Yard Assembles and ships the output of a number of nearby sawmills.
Concrete A mixture of cement, gravel and sand.
Concrete Mixer A machine with a large revolving drum in which concrete is mixed with other materials to make concrete.
Concrete plain. Concrete either without reinforcement, or reinforced only for shrinkage or temperature changes.
Concrete Spatula A flat piece of metal with a projecting handle used to smooth concrete footings.
Condensation. In a building: Beads or drops of water (and frequently frost in extremely cold weather) that accumulate on the inside of the exterior covering of a building when warm, moisture-laden air from the interior reaches a point where the temperature no longer permits the air to sustain the moisture it holds. Use of louvers or attic ventilators will reduce moisture condensation in attics. A vapor barrier under the gypsum lath or dry wall on exposed walls will reduce condensation in them.
Conditioning The exposure of a material to the influence of a prescribed atmosphere for a stipulated period of time or until a stipulated relation is reached between material and atmosphere.
Conduit Metal pipes used to contain electrical wiring in outdoor settings.
Conduit, electrical. A pipe, usually metal, in which wire is installed.
Conifer A type of tree that’s characterized by needle-like or scale foliage, usually evergreen; tree that is a gymnosperm, which comes with cones and needle-like shaped or scale-like leaves, producing wood known commercially as softwood.
Conservation Improvement, protecting, and wise use of natural resources according to principles that will assure utilization of the resource to obtain the highest economic and/or social benefits.
Consistency The property of a liquid adhesive by virtue of which it tends to resist deformation.
Construction dry-wall. A type of construction in which the interior wall finish is applied in a dry condition, generally in the form of sheet materials or wood paneling as contrasted to plaster.
Construction Lumber Lumber that is suitable for ordinary and light construction.
Construction, frame. A type of construction in which the structural parts are wood or depend upon a wood frame for support. In codes, if masonry veneer is applied to the exterior walls, the classification of this type of construction is usually unchanged.
Contact Angle The angle between a substrate plane and the free surface of a liquid droplet at the line of contact with the substrate.
Contour Cutting A flexible blade is necessary for contour cutting and for fairly wide curves the clumsy but efficient wooden bow to turning saw.
Convex An outward-curving shape.
Cooperage Containers consisting of two round heads and a body composed of staves held together with hoops, such as barrels and kegs.
Cope-and-Stick Joint A method of construction raised panel doors where the tongues of the rails (horizontal) connect to the grooves of the stiles (vertical).
Coped joint. See Scribing.
Copolymer Substance obtained when two or more types of monomers polymerize.
Corbel A projection from the face of a wall or column supporting a weight.
Corbel out. To build out one or more courses of brick or stone from the face of a wall, to form a support for timbers.
Cord A unit of measure often used for firewood stacked 4’ long x 4’ high x 8’ long.
Core Stock A solid or discontinuous center ply used in panel-type glued structures, such as furniture panels and solid or hollow-core doors.
Corner The line formed by the intersection of any two surfaces of a piece of lumber; not to be confused with ‘edge’.
Corner bead. A strip of formed sheet metal, sometimes combined with a strip of metal lath, placed on corners before plastering to reinforce them. Also, a strip of wood finish three-quarters-round or angular placed over a plastered corner for protection.
Corner boards. Used as trim for the external corners of a house or other frame structure against which the ends of the siding are finished.
Corner braces. Diagonal braces at the corners of frame structure to stiffen and strengthen the wall.
Cornerite. Metal-mesh lath cut into strips and bent to a right angle. Used in interior corners of walls and ceilings on lath to prevent cracks in plastering.
Cornice return. That portion of the cornice that returns on the gable end of a house.
Cornice. Overhang of a pitched roof at the cave line, usually consisting of a facie board, a soffit for a closed cornice, and appropriate moldings.
Cost and Freight (CF) Waterborne shipments to indicate that all loading charges and freight to final destinations are paid by the seller.
Cost, Insurance and Freight In addition to paying all the loading charges and freight to final destination, the seller pay insurance costs.
Counterflashing. A flashing usually used on chimneys at the roofline to cover shingle flashing and to prevent moisture entry.
Countersink A tool that allows you to drill a hole so that the head of a screw will sit flush with the face of a board.
Coupling Agent A molecule with different or like functional groups that is capable of reacting with surface molecules of two different substances, thereby chemically bridging the substances.
Covalent Bond A chemical bond that results when electrons are shared by two atomic nuclei.
Cove molding. A molding with a concave face used as trim or to finish interior corners.
Crack A large radial check resulting from greater tangential than radial shrinkage.
Crawl space. A shallow space below the living quarters of a basementless house, normally enclosed by the foundation wall.
Creep A time-dependent deformation of a wood member or adhesive joint due to sustained stress.
Cricket. A small drainage-diverting roof structure of single or double slope placed at the junction of larger surfaces that meet at an angle, such as above a chimney.
Crook A lumber defect where an edgewise warp effects the straightness of the board.
Cross Arms Designed to serve as the horizontal cross member of utility poles, generally rough sawn full, sizes range from 3”x4” to 4”x6” by 8’ long.
Cross Breaks Transverse planes of failure in tension parallel to the grain, caused by localized abnormal longitudinal shrinkage restrained by adjacent normal wood.
Cross Cut (crosscutting) A cut made perpendicular to the grain of a board.
Cross Grain The deviation of grain direction from the longitudinal axis of a piece of wood or from the stem axis in a tree. Pronounced deviation from the surface, especially in veneer, is termed short grain.
Crossbands In plywood with more than three piles, the veneers immediately beneath the faces, having grain direction perpendicular to that of the faces.
Cross-bridging. Diagonal bracing between adjacent floor joists, placed near the center of the joist span to prevent joists from twisting.
Crotch In lumber, this refers to a piece of wood taken from the fork of a tree. Crotch veneer is highly valued for its figuring.
Crotch Grain A figure produced by cutting centrally through a tree crotch in the common plane of both branches.
Crow Bar A straight bar of iron or steel, with the working end shaped like a chisel and often slightly bent and forked; used as a lever.
Crown Upper part of a tree, including branches and foliage.
Crown Class All trees in a stand whose tops and crowns occupy a similar position in the canopy or crown cover. The class into which the trees forming the crop or stand may be divided is on the basis of both their crown development and crown position relative to the crowns of adjacent trees and the general canopy.
Crown Cover Ground area covered by a crown; as delimited by the vertical projection of its outermost perimeter.
Crown Density Thickness, both spatially (depth) and in closeness of growth (compactness) of an individual crown as measured by its shade density. Collectively, crown density should properly be termed canopy density, as distinct from canopy cover.
Crown Height Vertical distance of a standing tree from ground level to the base of the crown, measured to the lowest live branch whorl or to the lowest live branch (excluding epicormics), or to a point halfway between the two.
Crown Length Vertical distance of a standing tree from the top of the leader to the base of the crown, measured to the lowest live branch whorl or to the lowest live branch (excluding epicormics), or to a point of halfway between the two.
Crown Length Ratio Of a standing tree, the ratio of a crown length to a tree height.
Crown molding. A molding used on cornice or wherever an interior angle is to be covered.
Crown Thinning Removing superfluous live growth in a tree crown to admit light, lessen wind resistance, and reduce weight.
CS Caulking Seam
CSG Casing
Cubic Scale Estimate of the cubic-foot volume of wood fiber in a log, tree, or other wood products.
Cumaru Color varies from golden tan to a reddish brown
Cup A defect in the lumber where the face of the board warps up like the letter “U”.
Cup Shake A split caused by lack of cohesion between the annual rings.
Cure The change in properties of an adhesive by chemical reaction and thereby develop maximum strength. This is generally accomplished by the action of hear or a catalyst, with or without pressure.
Curing The setting of an adhesive by chemical reaction. Also, the drying of wood, though this is not the preferred usage.
Curl A term to describe what happens to wood as it grows. Curly wood looks like sand on the beach or river bottom with repeated ripples in the grain. The grain goes up and down causing the unusual look in the wood. This is also called “Fiddleback” or “tiger” grain.
Curly Cherry Heartwood varies from rich red to reddish-brown
Curly Hard Maple Creamy-white with red tinge
Curly Soft Maple Creamy-white color
Curtain Coating Applying liquid adhesive to an adherent by passing the adherent under a thing curtain of liquid falling by gravity or pressure
Custom Drying Drying other people’s lumber
Custom Milling Surfacing or remanufacturing other peoples lumber on order.
Customer Sawing Sawing of lumber under contract, usually to given specifications.
Cut Stock Clear pieces that have been ripped and cross cut from ship type lumber, such as stiles, rails, muntins, window sash, intended for further manufacture.
Cut-Full Lumber Lumber intentionally manufactured in larger than normal thickness and width, usually to allow for shrinkage; a term sometimes confused with “full cut” lumber.
Cut-in brace. Nominal 2-inch-thick members, usually 2 by 4’s, cut in between each stud diagonally.
Cuttings When using hardwoods, portions of a board or plank having the quality required by a specific grade or for a particular use.
CWT Hundred Weights


D&M Dressed and Matched
d. See Penny.
D.B.H. Diameter at Breast Height
D/S (DS) Drop Siding
D2S Lumber that has been dressed on two sides.
Dado A rectangular channel cut partway into a board.
Dado. A rectangular groove across the width of a board or plank. In interior decoration, a special type of wall treatment.
Dark Grain Grain which is darker than the rest and should not be confused with pitch streaks.
Dead Blow Hammer A specialized mallet helpful in minimizing damage to the struck surface and in controlling striking force with minimal rebound from the striking surface.
Dead Load The weight of the structure itself; which includes built-in benches, the plank system, support structure and any railings, and other permanent features.
Death Watch Beetle A beetle that is about ¼ inch long and very destructive to structural beams.
Decay The decomposition of wood by fungi
Decay. Disintegration of wood or other substance through the action of fungi,
Decaying Knot A knot is disintegration of wood due to the action of wood-destroying fungi.
Deciduous Trees that have broad leaves that are shed in the fall. It is usually it is a hardwood.
Deck paint. An enamel with a high degree of resistance to mechanical wear, designed for use on such surfaces as porch floors.
Decking (DKG) Boards used for the surface of a deck; lumber expressed in nominal terms as being 2” to 4” thick and 4” and wider. Decking is usually surfaced to single tongue and groove in 2” nominal thickness. In 3” and 4” nominal thickness it may be double tongue and groove and worked with rounded or V edges, striated, or grooved. Decking is widely used for roofing and flooring.
Defect An irregularity found in a board that lowers its strength and value. Common defects are checks, knots, staining, etc. Conk, crook, decay, split, sweep, or other injury in the wood that decreases the amount of useable wood that can be obtained from a log.
Deflection The amount of sag in a counter, floor, joist, or shelf caused by the weight its supporting. Vertical distance between the chord and the skyline measured at midspan; frequently expressed as a percentage of the horizontal span length.
Defoliators Insects that destroy foliage.
Degrade Any defect that lowers the grade or quality of a log.
Dehumidifier Developed to reduce humidity in store rooms and basement conditions.
Delamination The separation of layers in laminated wood or plywood caused by failure of the adhesive itself or of the interface between adhesive and adhered.
Delignification Removal of part or all of the lignin from wood by chemical treatment.
Delimbing Gate Metal grid used with a skidder for removing limbs.
Dendrology Study of the identification of trees.
Density The weight of a body or substance per unit volume.
Density Rules A procedure for segregating wood according to density, based on percentage of latewood and number of growth rings per inch of radius.
Density. The mass of substance in a unit volume. When expressed in the metric system, it is numerically equal to the specific gravity of the same substance.
Depletion Allowance Deduction from taxable income derived from wasting assets. The Internal Revenue Code of the United States permits the calculation of depletion allowances either on the basis of a percentage of the gross income from the property in question or on a per-unit-of-product basis. Depletion differs from depreciation in that the asset subject to depletion cannot be replaced; a mine or an oil field cannot be replaced in the same manner that a factory or machine can be replaced.
Design Value A measurement of strength in lumber, involving basic properties of wood. They are: compression perpendicular to grain (Fcl), fiber stress in bending (Fb), horizontal sheer (Fv), modulus of elasticity (E), and tensions parallel to grain (Ft).
DET Double End Trimmed
Dewpoint The temperature at which atmospheric water vapor condenses out as a liquid.
Dewpoint. Temperature at which a vapor begins to deposit as a liquid. Applies especially to water in the atmosphere. Dimension. See Lumberdimension.
DF Douglas Fir
DF-L Douglas Fir-Larch
Diagonal Grain Cross grain exhibiting deviation of the growth-ring plane from the longitudinal axis, commonly the result of sawing boards other then parallel to the bark of the log.
Dial Gauge A measuring instrument with a circular graduated face and a pin which activates a rotating pointer to measure variation in movement in thousandths of an inch.
Diameter Classes Classification of trees based on the diameter of outside bark measured at D.B.H. In forest surveys, each diameter class encompasses approximately 2 inches: the 6-inch class would include trees 5.0 through 6.9 inches in D.B.H.
Diameter inside Bark (D.i.B.) Diameter measurement of a standing tree or log in which the estimated or actual thickness of the bark is discounted.
Diameter Limit Maximum diameter of trees to be cut, as in a timber sales contract.
Diameter outside Bark (D.o.B.) Measurement of trees diameter in which the bark is included.
Diameter Tape Tape measurer specially graduated so that diameter may be read directly when the tape is placed around a log or tree stem.
Dibble Spade-like tool used to prepare planting holes for seedlings. Dibbles are most commonly used in the South but are used in other areas for planting contained seedlings.
Diffuse-Porous Wood Certain hardwoods in which the pores tend to be uniform in size and distribution throughout each annual ring or to decrease in size slightly and gradually toward the outer border of the ring.
DIM Dimension
Dimension Framing lumber; generally applied to lumber when the nominal size is 2 inches thick and 2 or more inches wide. The National Grading Rule for Softwood Dimension Lumber defines “dimension” as lumber from 2 through 4 inches thick and 2 inches and wider.
Dimension Lumber Lumber that is from two inches thick up to, but not including, five inches thick, and that is also two or more inches in width. Dimensions can also be classified as framing, joists, planks, rafters, etc.
Direct Cost Cost that varies in direct proportion to production and is attributable to a specific factor of production.
Direct nailing. To nail perpendicular to the initial surface or to the junction of the pieces joined. Also termed face nailing.
Direct Seeding Spreading seeds over the forest seedbed by hand or machine. This practice is used to assist or supplement natural seed fall and to achieve regeneration.
Directional Felling Predetermining the way a tree will land when it hits the ground. When shears are used, the wedge-shaped blade provides a lever that directs the tree into its lay.
Discoloration Changes in the color of wood which affect only its appearance.
DKG Decking
Dolly Varden Siding A pattern with a thick and a thing edge and lap joint.
Dominant Trees The most numerous and vigorous species in a mixed forest. Larger-than-average trees with well-developed crowns extending above the general canopy level and receiving full light from above and partial light from the side.
Doorjamb, interior. The surrounding case into which and out of which a door closes and opens. It consists of two upright pieces, called side jambs, and a horizontal head jamb.
Dormer. An opening in a sloping roof, the framing of which projects out to form a vertical wall suitable for windows or other openings.
Dote Synonymous with ‘decay’ and are any form of decay which may be evident as either a discoloration or a softening of the wood.
Double End Trimmed (DET) Both ends cut reasonably square by a saw.
Double Spread Refers to application of adhesive to both adherents of a joint.
Double-Action Shear Mechanized cutting tool for felling trees; works like a pair of scissors. One blade is slightly offset, but both work against the other. Some work edge to edge.
Double-Drum Winch A winch consisting of two drums controlled separately, one for the dragline and the other from the haul-back line. Sometimes mounted on and powered by a tractor.
Dovetail Joint A method of joining wood at the corners by the use of interlocking pins and tails; a tenon that is shaped like a dove’s spread tail to fit into a corresponding mortise.
Dowel A wood pin used to align and hold two adjoining pieces.
Dowel Center A circular metal pin with a raised point that is inserted into a dowel hole and used to locate the exact center on a mating piece of wood.
Dowel Woodworking Tip A cylindrical wooden pin that is used to reinforce a wood joint.
Downspout. A pipe, usually of metal, for carrying rainwater from roof gutters.
Dozuki A type of Japanese woodworking saw that is used for fine joinery work such as dovetails. Its western equivalent is a back saw.
Draw Knife A tool having a blade with a handle at each end; by drawing it towards you, you can shave surfaces.
Drawer Slide A mechanism used to make drawers slide in and out.
Drawer Stop A device installed in a cabinet to limit the drawers’ movement.
Dressed and Matched (D&M) Lumber that has been worked with a tongue off center on one edge of each piece and a groove on the opposite edge to provide a close joint by fitting two pieces together.
Dressed and matched (tongued and grooved). Boards or planks machined in such a matter that there is a groove on one edge and a corresponding tongue on the other.
Dressing Shaping the cutting edge of a chisel to correct the bevel.
Drier paint. Usually oil-soluble soaps of such metals as lead manganese, or cobalt, which, in small proportions, hasten the oxidation and hardening (drying) of the drying oils in paints.
Drill An implement with cutting edges or a pointed end for boring holes in hard materials, usually by a rotating abrasion or repeated blows; a bit.
Drip cap. A molding placed on the exterior top side of a door or window frame to cause water to drip beyond the outside of the frame.
Drip. (a) A member of a cornice or other horizontal exterior finish course that has a projection beyond the other parts for throwing off water. (b)A groove in the under. side of a sill or drip cap to cause water to drop off on the outer edge instead of drawing back and running down the face of the building.
Drive Wheel The portion of a band saw’s pulley-like drive system that propels the blade forward.
Dry Seasoned, usually to a moisture content of less than 19%.
Dry Kiln An enclosed chamber in which temperate and humidity conditions are subject to control for the purpose of drying lumber.
Dry Rot A term loosely applied to many types of decay but especially to that which, when in an advanced stage, permits the wood to be easily crushed to a dry powder; the term is actually a misnomer for any decay, since all fungi require considerable moisture for growth.
Dry Strength The strength of an adhesive joint determined immediately after drying under specified conditions or after a period of conditioning in a standard laboratory atmosphere.
Drywall A paneling product used as an interior wall and ceiling covering made of gypsum plaster with paper facings. The gypsum plaster may be reinforced with recycled fiber.
Drywall. Interior covering material, such as gypsum board or plywood, which is applied in large sheets or panels.
Ducts. In a house, usually round or rectangular metal pipes for distributing warm air from the heating plant to rooms, or air from a conditioning device or as cold air returns. Ducts are also made of asbestos and composition materials.
Dunnage Generally lumber of a low grade used to separate and bind ship cargo; stakes, stripes and other pieces that are needed in holding and protecting merchandise on railroad cars and truck shipments.
Durability A general term for permanence or lastingness; frequently used to refer to the degree of resistance of a species or of an individual piece of wood to attack by wood-destroying fungi under conditions that favor such attack.


E Edge
E&CB2S Edge & Center Bead Two Sides
E&CV1S Edge & Center V One Side
E&CV2S Edge & Center V Two Sides
Early Wood (Springwood) The first part of the trees’ rings to form after winter hibernation. Earlywood is often characterized by larger cells and a lower density.
Earned Harvest A timber management concept used by the USDA Forest Service. This allows the timber manager an immediate increase in the allowable cut when the manager applies intensive management techniques that will accelerate future timber growth.
Eased Edges (EE) Slightly rounded surfacing on pieces of lumber to remove sharp corners. Lumber 4 inches or less in thickness is frequently shipped with eased edges unless otherwise specified.
Easement A legal right for restricted use of property by the easement holder. Easements are granted to utility companies so they may service the utility lines running through a property. Decks should not be built on the area described by an easement because access granted by the easement may require the deck to be torn down or removed.
Eaves. The margin or lower part of a roof projecting over the wall.
EB1S Edge bead one side.
EB2S Edge bead two sides.
Ecology The study of animals and plants in relation to their biological and physical surroundings.
Ecosystem Complex ecological community and environment forming a functional whole in nature.
Edge The narrow face of a rectangular-shaped piece of lumber.
Edge Banding Veneer that usually has an adhesive to stick to plywood edging.
Edge Grain Lumber sawed parallel with the pith of the log and approximately at right angles to the growth rings; that is, the rings form an angle of 45 degrees or more with the wide face if the piece.
Edge Guide A straightedge that is used to guide tools, such as a circular saw or router, along a work-piece.
Edge Joining Smoothing and squaring the edge of a board so that it can be glued up evenly to another piece.
Edge Trimmer Tool used to trim edge banding.
EE Eased Edges
EG Edge (vertical) Grain
Elasticity A property of a material that causes it to return to its original dimensions after being deformed by loading.
Elastomer A macromolecular material that, at room temperature, is deformed by application of a relatively low force and is capable of recovering substantially in size and shape after removal of the force.
Elbow In a dust collection system, a fitting used to torn corners.
Electron Beam Welding A metal joining process that uses a narrow stream of electrons to produce a highly concentrated heat source.
Elevated Deck A deck requiring a structure of beams, footings, and posts to raise it to the desired level. Often used so that the height of the deck is the same as interior floors, making access to the deck from the house easier.
EM End Matched
Embedded Grit Grit that is embedded in wood chips in the process of whole-tree chipping. This grit may be extremely difficult to remove when using chips in paper and pulp manufacture.
Embrittlement A loss in strength or energy absorption without a corresponding loss in stiffness. Clear, straight grained wood is generally considered a ductile material; chemical treatments and elevated temperatures can alter the original chemical composition of wood, thereby embrittling the wood.
Empty-cell Process Any process for impregnating wood with preservatives or chemicals in which air is imprisoned in the wood under the pressure of the entering preservative and then expands, when the pressure is released, to drive out part of the injected preservative.
Encased Knot The dead portion of a branch embedded in the stem by subsequent growth of a tree.
End Checks A drying defect caused by the ends of the boards drying faster than the rest of the wood. This can usually be prevented by sealing the end grain. Using an end grain sealant protects against end checks in decking.
End Coating The process of sealing the ends of the boards to prevent checking caused by unrestrained evaporation of moisture. Also known as “end grain sealing.”
End Grain Lumber grain as seen from one end of the board where elongated pores are exposed. End grain can absorb and release liquid and liquid vapors.
End Joists The joists at the end of a series of parallel joists.
End-Match (EM) To tongue and groove the ends of matched lumber.
End-Split A lengthwise separation of the wood fibers at the end of a piece of lumber.
Energy Wood Wood that has been delivered to paper and pulp mills, specifically for burning in boilers; wood to be utilized for heat or other energy products. This includes forest, industrial, urban, and other wood waste, as well as whole-tree chips.
Epidermis The outermost layer of cells on the primary plant body; often with strongly thickened and cuticularized outer walls; sometimes consisting of more than one layer of cells.
Epoxy Glue A two part glue that practically glues anything to anything, including metal to metal.
Equilibrium Moisture Content (EMC) When the level of moisture in a board is equal to the moisture in the surrounding air.
ES Englemann Spruce
European Hinge A hidden style hinge fastened to the door with a cup hole.
EV1S Edge V one side
EV2S Edge V two sides
Even-Aged A stand of trees in which there are only small differences in age among the individual trees.
Even-Aged Management A silvicultural system in which the individual trees originate at about the same time and are removed in one or more harvest cuts, after which a new stand is established.
Expansion and Contraction Boards expand when they heat up and contract when they cool down. This must be accounted for when spacing deck boards.
Expansion joint. A bituminous fiber strip used to separate blocks or units of concrete to prevent cracking due to expansion as a result of temperature changes. Also used on concrete slabs.
Export Sale Sale of lumber to be shipped to a foreign country.
Exporter Wholesaler or broker selling to a foreign market.
Extender A substance, generally having some adhesive action, added to an adhesive to reduce the amount of the primary binder required per unit area.
Extension Cord A flexible, insulated, electric wire fitted with a plug at one end and one or more outlets on the other, allowing one to plug in.
Extractives Substances in wood, not an integral part of the cellular structure, that can be dissolved out with hot or cold water, ether, benzene, or other relatively inert solvents.
Extreme Fiber Stress in Bending (Fb) The allowable unit stress used in the design of bending members such as beams, trusschords, joists, and rafters.
Extrusion Spreading A method of adhesive application in which adhesive is forced through small openings in the spreader head.


Face When a board has one side that is wider than the other, the wider side is referred to as the face (as opposed to the edge). This may also refer to the side that is to visible in the finished item.
Face Flaps Used for writing bureaus and cabinets where it is essential to preserve an uninterrupted flush writing surface are hinged with back flap hinges, and can be rebated/rabbeted over the carcass sides.
Face Frame In cabinetmaking, a face frame is a flat frame attached to the front of a carcase. The face frame is used to conceal the exposed edges of plywood panels used to build the carcase.
Face Side The wide surface of a piece of lumber; the wide surface showing the better quality or appearance from which a piece is graded.
Face Veneer High quality veneer that is used for exposed surfaces on plywood.
Face Width The width of the face of any piece of lumber; in tongued or lapped (rabbeted) lumber, it does not include width of tongue or lap.
Facia or fascia. A flat board, band, or face, used sometimes by itself but usually in combination with moldings, often located at the outer face of the cornice.
Factory Lumber Lumber intended to be cut up for use in further manufacture’ it is graded on the basis of the percentage of the area which will produce a limited number of cuttings of a specified, or a given minimum, size and quality.
Fall-Down Lumber not up to a particular grade.
FAS (First and Second) Mixed domestic hardwood lumber grade is the highest grade of hardwood lumber. In most species, a board must be 6” or wider, 8’ or longer. Walnut and butternut are the exceptions.
Fascia (facia) A broad, flat, horizontal surface, sometimes used to cover a joint, or as the other edge of a cornice.
Fasteners Generic term for bolts, nails, bolts, and other connecting devices.
Fb Extreme fiber stress in bending
FBM Feet board measure
FCPW Flat car paper wrapped
Featherboard A piece of wood with thin “fingers” that hold a board against a fence or down against the table of a power tool; usually a table saw or router.
Feed Rate The distance that the stock being processed moves during a given interval of time or operation cycle.
Feet Board Measure (FBM, FT, BM) A term used to indicate a specific unit of measure.
Feet Surface Measure (FTSM) A term used to indicate a specific unit of measure
Fence A straight guide to keep a board a set distance from a blade or other cutters.
FG Flat of slash grain.
Fiber Saturation Point The stage in the drying or wetting of wood at which the cell walls are saturated and the cell cavities free from water. It applies to an individual cell or group of cells, not to whole boards.
Fibril A threadlike component of cell walls, invisible under a light microscope.
Fiddleback A type of washboard-like figure that occurs in some species of wood with wavy grain; a decorative wood figure caused by wavy grain. Fiddleback veneer is prized for its character and widely used for musical instruments.
Figure Any distinctive appearance on a longitudinal wood surface resulting from anatomical structure, irregular coloration or defects.
Figured Bubinga Medium red-brown with purple veining
Filler A substance that is used to fill pores and irregularities on the surface of material to decrease the porosity before applying a finishing coat.
Filler (wood). A heavily pigmented preparation used for fining and leveling off the pores in open-pored woods.
Filtch A thick piece of lumber with or without wane (bark) on one or more edges suitable for remanufacturing.
Finger Joint A method of joining two pieces of lumber end-to-end by sawing a set of projecting “fingers” that interlock into the end of each piece. This makes for a strong glue joint when the pieces are pushed together.
Finish A term indicating the higher grades of lumber, sound, relatively free of blemishes.
Finished Size The net dimensions after surfacing.
Fir Any evergreen coniferous tree, especially of the genus Abies, with needles borne singly on the stems.
Fire Endurance A measure of the time during which a material or assembly continues to exhibit fire resistance under specified conditions of test and performance.
Fire retardant chemical. A chemical or preparation of chemicals used to reduce flammability or to retard spread of flame.
Fire Retardant Treated Wood As specified in building codes, a wood product that has been treated with chemicals by a pressure process of treated during the manufacturing process for the purpose of reducing its flame spread performance in an ASTM E 84 test conducted for 30 minutes to performance levels specified in the codes.
Fire stop. A solid, tight closure of a concealed space, placed to prevent the spread of fire and smoke through such a space. In a frame wall, this will usually consist of 2 by 4 cross blocking between studs.
Fire-resistive. In the absence of a specific ruling by the authority having jurisdiction, applies to materials for construction not combustible in the temperatures of ordinary fires and that will withstand such fires without serious impairment of their usefulness for at least 1 hour.
Fire-Retardant A chemical applied to lumber or other wood products to slow combustion and flame spread.
Firm Heart Stain A brownish or reddish discoloration, and in the grades where specified, does not affect the use of the piece to any greater extent than the other characteristics of the grade.
Fishplate. A wood or plywood piece used to fasten the ends of two members together at a butt joint with nails or bolts. Sometimes used at the junction of opposite rafters near the ridge line.
Fittings For dust collection, accessories that are used to connect hoses, pipes, and tools within a dust collection system.
Flagstone (flagging or flags). Flat stones, from 1 to 4 inches thick, used for rustic walks, steps, floors, and the like.
Flake A small flat wood particle of predetermined dimensions, uniform thickness, with fiber direction essentially in the plane of the flake; in overall character resembling a small piece of veneer.
Flame Spread The propagation of a flame away from the source of ignition across the surface of a liquid of a solid, or through the volume of a gaseous mixture.
Flashing. Sheet metal or other material used in roof and wall construction to protect a building from water seepage.
Flat Car Paper Wrapped (FCPW) Lumber loaded on an open rail car after being strapped into units and wrapped in weather resistant material. Plastic or papers are commonly used.
Flat Grain (F.G.) Lumber sawn approximately parallel to the annual growth rings so that all or some form an angle of less then 45 degrees with the surface of the piece.
Flat paint. An interior paint that contains a high proportion of pigment and dries to a flat or lusterless finish.
FLG Flooring
Flooring A lumber pattern with smooth face and tongue and groove edges.
Flue lining. Fire clay or terra-cotta pipe, round or square, usually made in all ordinary flue sizes and in 2-foot lengths, used for the inner lining of chimneys with the brick or masonry work around the outside. Flue lining in chimneys runs from about a foot below the flue connection to the top of the chimney.
Flue. The space or passage in a chimney through which smoke, gas, or fumes ascend. Each passage is called a flue, which together with any others and the surrounding masonry make up the chimney.
Flush When two adjoining surfaces are perfectly even with one another.
Fly rafters. End rafters of the gable overhang supported by roof sheathing and lookouts.
FOB Free on board
FOHC Free of heart center
Foot (FT) A unit of lineal measurement usually used to indicate the length of lumber.
Footing The below-ground support of a deck’s post; usually made from concrete.
Footing. A masonry section, usually concrete, in a rectangular form wider than the bottom of the foundation wall or pier it supports.
Forest Area managed for the production of timber and other forest productions or maintained as wood vegetation for such indirect benefits as protection of catchment areas or recreation.
Forest Economics The branch of forestry concerned with the forest as a productive asset subject, in relation to economic principles.
Forest Floor A general term for the surface layer of soil supporting forest vegetation; includes all dead vegetation on the mineral soil surface in the forest as well as litter and unincorporated humus.
Forest Management The practical application of scientific economic, and social principles to the administration and workings of a specific forest area for specified objectives.
Forest Practice Any activity that enhances and/or recovers forest growth or harvest yield, such as fertilization, harvesting, planting, site preparation, and thinning. Road construction or reconstruction within forest lands for the purpose of facilitating harvest or forest management. Any management of slash, resulting from the harvest or improvement of tree species.
Forest Residuals Sum of unused and wasted wood in the forest, including logging residues, annual mortality, and dead, rough, and rotten trees. Unmerchantable material normally left following conventional logging operations other than whole-tree harvesting.
Forest Stewardship Council An independent, non-governmental organization established to promote responsible management of the worlds forests and is probably the most well-known forest certification program worldwide. FCS standards of responsible forestry are applied to management of the forest land. A chain-of-command (COC) certification ensures that forest products that carry the FSC label can be tracked back to the certified forest from which they came.
Forest Type Classification of forest land in terms of potential cubic-foot volume growth per acre at the culmination of mean annual increment (C.M.A.I.), in fully stocked natural stands. Classification of forest land is based on the species forming a plurality of live-tree stocking. Type is determined on the basis of species plurality of all live trees that contribute to stocking.
Forestation Establishment of a forest, artificially or naturally, or an area, whether previously forested or not.
Forestry A profession embracing the art of creating, business, and science, conserving, and managing forests, and forest lands for the continuing use of their materials, resources, and other forest products.
Formica Composed of layers of Kraft paper impregnated with phenolic resins.
Forster Bit These have a center spur and circular timbers with cutting teeth that cut clean flat bottomed holes.
Found Curve Naturally occurring crooked timbers usually with two sides sawn and two sides with the bark removed; used as beams, knee braces, and posts.
Foundation. The supporting portion of a structure below the first floor construction, or below grade, including the footings.
Framing Lumber used for structural members in a house or other building. This is the skeleton to which floors, roofs, and sides are attached.
Framing Chisel A large chisel with long, heavy blades, strong enough to be hit with a heavy mallet.
framing for a chimney, stairway, or other opening.
Framing Lumber A term generally applied to lumber when the nominal size is 2 through 4 inches thick and 2 inches and wider; lumber used to construct a building or structure.
Framing Square A flat piece of metal shaped like an “L”, with measurements along both legs of the “L”; commonly used when building decks for marking lines perpendicular to the length of lumber.
Framing, balloon. A system of framing a building in which all vertical structural elements of the bearing walls and partitions consist of single pieces extending from the top of the foundation sin plate to the roofplate and to which all floor joists are fastened.
Framing, platform. A system of framing a building in which floor joists of each story rest on the top plates of the story below or on the foundation sill for the first story, and the bearing walls and partitions rest on the subfloor of each story.
Free Along Side Seller delivers the shipment within reach of ship’s loading tackle. All dock charges and freight from point of origin to the dock have been paid by the seller. Freight charges to the final destination are billed to the buyer.
Free of Heart Center (FOHC) Lumber sawn to exclude the heart center or pith of the log.
Free on Board (FOB) Refers to a named point to which the seller will deliver and load lumber on board transportation equipment at no additional charge to the buyer. Freight or other charges to final destination are for the buyers account.
Free Water Moisture found in the cell cavities of wood.
Freestanding Platform Deck A deck supported entirely by its own structure, typically used for remote decks.
Freight Measure “Board Measure” contents of lumber-when calculated from measurements of over-all dimensions; it is used only for displacement measurements for freight purposes.
Fret Saw A saw with a very fine toothed blade used for delicate cuts in thin material.
Friction A saw blade made with one piece of carbon steel used at high speeds to soften metal for removal.
Friction Sawing Usually a type of band sawing that uses high speed to generate heat to soften the metal in front of the blade.
Frieze. In house construction a horizontal member connecting the top of the siding with the soffit of the cornice.
Frostline. The depth of frost penetration in soil. This depth varies in different parts of the country. Footings should be placed below this depth to prevent movement.
FRT Freight
FT Foot
FT SM Feet surface measure
Full Length Cut so the ends can be squared to exact length tallied.
Full Sawn Lumber Green Lumber, cut full to a specified size without variation undersize at time or original inspection.
Full-Cell Process Any process for impregnating wood with preservatives or chemicals, in which a vacuum is drawn to remove air from the wood before admitting the preservative.
Full-Cut Lumber Lumber that in thickness and width measures fully up to specified sizes; a term sometimes confused with ‘cut-full’ lumber, the latter admitting lumber intentionally manufactured in larger than nominal thickness and width.
Fungi, wood. Microscopic plants that live in damp wood and cause mold, stain, and decay.
Fungicide A chemical that kills fungi; used to control fungal diseases in greenhouses and nurseries.
Fungicide. A chemical that is poisonous to fungi.
Fungus Stain Lumber stain caused by fungus growth in wood; fungi can be either of the sapwood-staining or decay-producing types.
Furnish Wood material that has been reduced for incorporation into conventional wood-based composites; including flakes, particles, and fiber.
Furring. Strips of wood or metal applied to a wall or other surface to even it and normally to serve as a fastening base for finish material.


G/S Grade-Stamped
Gable end. An end wall having a gable.
Gable. In house construction, the portion of the roof above the eave line of a double-sloped roof.
Gage The side-to-side thickness of a band saw blade.
Galvanize Coating a piece of metal with zinc, a metal that resists corrosion. Look for hot-dipped galvanized pieces when selecting metal parts for a deck. The hot-dipped method of galvanized metal provides more protection than coated galvanizing.
Gauge A tool used to determine depth, width, and/or height of an object.
Gelatinous Fibers Modified fibers that are associated with tension wood in hardwoods.
Generator A machine that converts one form of energy into another; especially mechanical energy into electrical energy, as a dynamo, or electrical energy into sound, as an acoustic generator.
Girder A large or principal beam used to support concentrated loads at isolated points along its length.
Girder. A large or principal beam of wood or steel used to support concentrated loads at isolated points along its length.
Girt Major horizontal timber that connects posts.
Girth The distance around a tree; circumference.
Gloss (paint or enamel). A paint or enamel that contains a relatively low proportion of pigment and dries to a sheen or luster.
Gloss enamel. A finishing material made of varnish and sufficient pigments to provide opacity and color, but little or no pigment of low opacity. Such an enamel forms a hard coating with maximum smoothness of surface and a high degree of gloss
Glue Originally, a hard gelatin obtained from hides, tendons, cartilage, bones, etc., of animals; also, an adhesive prepared from this substance by heating with water. Through general use, the term is now referred to as ‘adhesive’.
Glue Joint A special interlocking groove pattern that is used to join two pieces, edge to edge, securely.
Glue Laminating Production of structural or nonstructural wood members by bonding two or more layers of wood together with adhesive.
Glulam A shorthand version of glue laminate. Glue lamination is a process in which individual pieces of lumber or veneer are bonded together with an adhesive to make a single piece, with the grain of each piece parallel to the grain of each of the other pieces.
Goncalo Alves (Tigerwood) Reddish-brown heartwood
Good One Side Plywood with one side patched solid and sanded, the other side will be rough and have open knot holes.
Gouge A chisel like tool with a curved cutting edge.
Grade A designation of the quality of a log or wood product such as lumber, plywood, or veneer.
Grade Mark A stamp or symbol indicating the grade, quality, and/or intended use of a piece of lumber, plywood, or other wood products. To be recognized as “grade marked”, the product must bear an official stamp issued by a grading agency and must be applied by a qualified grader; or it must be accompanied by a certificate attesting to the grade.
Grade Stamped Grade indicated with official stamp impression.
Grade-Level Deck A deck flush with, or slightly above, ground level. Grade-level deck joists usually rest directly on the footings or piers below.
Gradient Amount by which the grade decreases or increases in a unit of horizontal distance.
Grading Rules A set of criteria by which to judge various pieces of lumber of panels in terms of appearance, strength, and suitability for various uses. Regional grading agencies draw up rules for grading based on the voluntary product standards issued by the US Bureau of Standards.
Grain A general term referring to the alignment, appearance, arrangement, color, direction, and size of wood fibers in a piece of lumber. Among the many types of grain are coarse, curly, fine, flat, open, spiral, straight, and vertical.
Grain, edge (vertical). Edge-grain lumber has been sawed parallel to the pith of the log and approximately at right angles to the growth rings; i.e., the rings form an angle of 45° or more with the surface of the piece.
Grain, flat. Flat-grain lumber has been sawed parallel to the pith of the log and approximately tangent to the growth rings, i.e., the rings form an angle of less than 45° with the surface of the piece.
Grain, quartersawn. Another term for edge grain.
Grain. The direction, size, arrangement, appearance, or quality of the fibers in wood.
Green Lumber (Live) Freshly cut, unseasoned, not dry. Lumber with a moisture content of 30% or more.
Grit A measure of the size of abrasive particles used in the manufacturing of sandpaper. Grit can also be measured as the number of particles in a square inch of sandpaper surface.
Gross Measure ‘Board Measure’ contents of lumber when calculated from measurements of named sizes; same as nominal measure.
Ground Clearance General term for removing unwanted roots, slash stumps, stones, and vegetation from a site before Afforestation or reforestation. Generally, the distance by which a vehicle’s lowest point, exclusive of the wheel assembly, clears the ground; measured perpendicularly from that point to a plane surface on which the vehicle rests.
Ground Length Extent to which the ground around a tree is broken by gullies, or swells ridges, rock outcrops, and sharp slope changes.
Ground-Fault Circuit Interrupter (GFCI) An electrical safety device that instantly shuts down a circuit if leakage occurs; greatly reduces the risk of electrical shock. These devices are built into outlets and are required by code for outdoor receptacles.
Grounds. Guides used around openings and at the floorline to strike off plaster. They can consist of narrow strips of wood or of wide subjambs at interior doorways. They provide a level plaster line for installation of casing and other trim.
Grout. Mortar made of such consistency (by adding water) that it will just flow into the joints and cavities of the masonry work and fill them solid.
Growth Ring The layer of wood growth put on a tree during a single growing season.
Guillotine Shear Type of carrier-mounted, single-action anvil shear used in mechanized cutting where the blade is pushed through the stem and away from the carrier, instead of being pulled as in the draw shear.
Gullet The curved area between two band saw teeth into which the chip curls.
Gullet Depth The distance from the tooth tip to the bottom of the gullet.
Gum Canal An intercellular cavity, found in woods that may contain gum, latex, and resins.
Gum Pocket An excessive local accumulation of gum or resin in the wood.
Gunstock Post A post having an increased size at its top, providing extra strength for intersecting joinery.
Gusset. A flat wood, plywood, or similar type member used to provide a connection at intersection of wood members. Most commonly used at joints of wood trusses. They are fastened by nails, screws, bolts, or adhesives.
Gutter or nave trough. A shallow channel or conduit of metal or wood set below and along the eaves of a house to catch and carry off rainwater from the roof.
Gypsum plaster. Gypsum formulated to be used with the addition of sand and water for base-coat plaster.


H or M Hit or Miss
H&M Hit and Miss
Hacksawing The use of a long blade mounted in a bow-shaped frame. Cutting takes place using a reciprocating, or back-and-forth, motion.
Half-Blind Dovetail A dovetail joint where the cut does not go all the way through the board. The ends of a half-blind dovetail are concealed.
Half-Lap A joint in which two timbers are let into each other.
Hammer A hand tool with a heavy rigid head and a handle; used to deliver an impulsive force by striking.
Hammer Beam A horizontal timber projecting from the top of the wall or rafter that supports a wood truss. The design creates a large roof span with relatively short timbers.
Hammer Drill (Rotary Hammer) A rotary drill with a hammering action. The hammering action provides a short, rapid hammer thrust to pulverize relatively brittle material and provide quicker drilling with less effort.
Hand Plane A tool to smooth and true wood surfaces, consisting of a blade fastened in frame at an angle with hand grips to slide it along the board. There are several different parts that make up a hand plane:
Hand Tools Are the basic tools of woodworking and the processes of sawing, chiseling, and smoothing wood.
Hand-Hewn A timber squared off and shaped by hand.
Hang-Up A vehicle moved by a pair of short, endless articulated belts, called tracks, driven by tractor tires. Steering is by a pair of ordinary wheels in front. The whole vehicle is termed a half-track.
Hard Maple Creamy white with a reddish tinge
Hardboard A type of manufactured board similar to particle board but with a much smoother surface. A common brand of hardboard is Masonite.
Hardener A substance or mixture of substances that is part of an adhesive and is used to promote curing by taking part of the reaction.
Hardness The property of wood that is indicated by a resistance to cutting, scratching, denting, pressure or wear.
Hardwood A general term referring to any variety of broad-leaved, deciduous trees, and the wood from those trees. The term has nothing to do with the actual hardness of the wood; some hardwoods are softer then certain softwood (evergreen) species.
Hardwood Wrench A tool used to hold deck boards straight while fasteners are being installed. It locks into place and applies much more bending power then other methods of straightening deck boards.
Harvesting Removing merchantable trees.
Harvesting Machine Classifications The mobile machinery used in forestry, then is classified into major types by the specific functions or combination of functions preformed. Further classification may be required to differentiate between machines with basic conceptual differences that effect recognition of performance but perform the same functions. One or more of the following sub-classifications may be used when necessary. Multifunction machines are named by a composite of the functions, listed in the order the functions are preformed.
Haul Conveying wood from a loading point to an unloading point.
Haul-Back Block Block used to guide the haul-back line.
Haul-Back Line Rope used in cable logging to haul the main line and its fittings back to the point where the logs are to be attached.
Haunch The part of the whole timber beyond the shoulder which is let into another timber.
Haywire Operation Contemptuous term for logging operation that has poor equipment.
HB Hollow Bark
Head Rig Principal machine in a sawmill; used for initial breakdown of logs by sawing along the grain. Logs are first cut into cants on the head rig before being sent on to other saws for further processing. This is also known as head saw.
Head Saw In a sawmill, the large band saw or circular saw used to size the log into lumber.
Head Tree Spar tree at the landing of a skyline logging operation. This is also known as Head Spar.
Header A beam fitted between trimmers and across the ends of tailpieces in a building frame; a horizontal support at the top of an opening.
Header. (a) A beam placed perpendicular to joists and to which joists are nailed in framing for chimney, stairway, or other opening. (b) A wood lintel.
Heart Content Hardwood is formed when sapwood becomes inactive and is infused with additional resin compounds. It develops slowly in the center of the tree as the tree matures. The older the tree, the higher the heart content.
Heart Pith The soft, spongy heart of a tree, which may appear on the surface of sawn timber.
Heart Shake A split that starts at the heart of a log.
Heart Stain A discoloration of the heartwood.
Hearth. The inner or outer floor of a fireplace, usually made of brick, tile, or stone.
Heartwood The dead inner core of a tree. Usually must be harder and darker than the new wood.
Heartwood. The wood extending from the pith to the sapwood, the cells of which no longer participate in the life processes of the tree.
Heel Boom Loading boom that uses tongs to heel or force one end of a log against the underside of the boom.
Heel Tackle System of lines and blocks used to tighten the skyline.
HEM Hemlock
Hem-Fur Hemlock – True Firs
Hemicelluloses A cellulose-like material in wood that is easily decomposable as by dilute acid.
Herbicide Chemical used to kill or retard the growth of plants; weed killer.
Herringbone Pattern In veneering, a herringbone pattern that is formed when successive layers of veneers are glued up so they form a mirror image. Usually this pattern slants upwards and outwards, similar to a herringbone.
Hickory Brown to reddish-brown color
Hide Glue Prepared by boiling bones, hides, etc. in water, and obtaining a hard cake form which must be broken up in an old piece of sacking and soaked for 12 hours before heating.
High Grade Good quality timber.
High Rigger Logger who tops trees and rigs them with blocks, guys, and lines.
High Stump A stump that is higher then a specified standard.
High-Lead Logging Wire rope system that involves yarding in logs or trees by means of a rope passing through a block at the top of the head spar.
High-Speed Steel A particular grade of steel that offers improved hardness and wear resistance. High-speed steel is often used to make various cutting tools.
Hinge A mechanical device that connects two solid objects, allowing rotation between them.
Hip roof. A roof that rises by inclined planes from all four sides of a building.
Hip. The external angle formed by the meeting of two sloping sides of a roof.
Hit and Miss In surfaced lumber, hit and miss is a series of skips by planer knives with surfaced or entirely rough.
Hit or Miss Pits or spots in wood caused by fungi. It develops in the living tree and does not develop further in wood in service.
Hog Machines used to grind wood into chips for use as fuel or for other purposes. The wood used for this is usually wasted wood unfit for lumber or other uses.
Hogged Fuel Fuel made by grinding wasted wood in a hog; a mix of wood residues such as sawdust, planer shavings, and sometimes coarsely broken-down bark and solid wood chunks produced in the manufacturing of wood products and normally used as fuel.
Hold Down A type of iron clamp, fitting into a hole in a bench; tightened or loosened by hammer taps.
Holding Wood When felling timber, this is the part of a tree left uncut until the end in order to hold the fall of the tree in the desired direction.
Hollow Grinding A concave bevel on a chisel, gouge, or knife.
Hollow-Core Construction A panel construction with faces of plywood, hardboard, or similar material bonded to a framed-core assembly of wood lattice, paperboard rings, which support the facing at spaced intervals.
Holly Cream-white heartwood
Honeycomb A drying defect that occurs when the lumber undergoes severe case hardening in the early stages of drying; appears as deep, internal checks.
Hook A tooth form that has evenly spaced teeth, wide gullets, and a positive rake angle.
Horizontal Boring An alternative to mortise and tenon joint; has two drilling heads, side by side and usually an adjustable table for height.
Horned Dado This is caused by the outside blades of a stacked dado head cutting deeper than the chipper blades.
Hot Logging Logging system operation in which the logs are not stored or decked, but loaded onto a truck as soon as they are skidded to a landing.
Housing The shallow mortise or cavity for receiving the major part of a time end, generally copied with a smaller deep mortise to receive a tenon tying the joint together.
Humidifier. A device designed to increase the humidity within a room or a house by means of the discharge of water vapor. They may consist of individual room size units or larger units attached to the heating plant to condition the entire house.
Hundred Lineal Feet (CLF) A term used to indicate unit of measurement.
Hundredweight (CWT) A unit of weight, used by carriers as a basis to measure freight rates on lumber shipments.
Hydraulic Barking Removal of bark from round timber, such as bolts, logs, or billets, by high-pressure jets of water as the pieces are mechanically rotated in a closed chamber.
Hydrogen Bond An intermolecular attraction force that results when the hydrogen of one molecule and a pair of unshared electrons on an electronegative atom of another molecule are attracted to one another.
Hydrophilic Having a strong tendency to bind or absorb water.
Hydrophobic Having a strong tendency to repel water.
Hydroscopic The tendency of wood to absorb and expel moisture as humidity levels change.


I-beam. A steel beam with a cross section resembling the letter I. It is used for long spans as basement beams or over wide wall openings, such as a double garage door, when wall and roof loads are imposed on the opening.
IC Incense Cedar
Idle Time Scheduled non-operating time.
Idler Wheel In band sawing, it is the unpowered half of the pulley-like system that turns the blade. Its primary purpose is to guide the blade.
IIC. A new system utilized in the Federal Housing Administration recommended criteria for impact sound insulation.
I-Joist A beam whose cross section resembles the letter “I”. One in which the top and bottom flanges (such as 2x4s) are connected by thinner material (such as OSB or plywood).
Imbuia Yellow-olive heartwood
Impreg. Wood in which the cell walls have been impregnated with synthetic resin so as to reduce materially its swelling and shrinking.
IN Inch or inches.
Incipient Decay An early stage of decay in which hyphae have invaded the cell structure, sometimes discoloring the wood, but have not perceptibly reduced the hardness of the wood.
Incised Wood Wood with slots cut into the side of the wood so that preservative chemicals can penetrate more deeply during pressure treatment. Western species of wood don’t absorb preservative chemicals as easily as some woods and require incising so that enough of the preservative enters the wood.
Included Sapwood Areas of light-colored wood, apparently sapwood, found within the portion of stem that has becomes heartwood.
Increment Borer A tool used to take a small core from the bole of a tree to determine growth rate.
IND Industrial
Independent One who logs and sells his output on the open market; not associated with a mill or under a company/dealer contract.
Independent One who logs and sells his output on the open market; not associated with a mill or under a company/dealer contract.
Industrial (IND) A term for lumber destined for remanufacture such as industrial clears, moulding stock and shop.
Industrial Wood All round wood products excluding fuel wood.
Infeed The direction a work piece is fed into a blade or cutter.
Inlay Covers the practice of inletting any one material into another material of different color or composition.
Inorganic-Bonded Composites Manufactured wood-based composites where an inorganic binder, typically gypsum or magnesia-cement, acts as a continuous matrix and fully encapsulates the wood elements.
INR (Impact Noise Rating). A single figure rating which provides an estimate of the impact sound insulating performance of a floor-ceiling assembly.
Inset An area of a deck that has been cut out to accommodate landscape elements such as trees.
Insulation board, rigid. A structural building board made of coarse wood or cane fiber in ½- and 25/32-inch thickness It can be obtained in various size sheets, in various densities, and with several treatments.
Insulation, thermal. Any material high in resistance to heat transmission that, when placed in the walls, ceiling, or floors of a structure, will reduce the rate of heat flow.
Intarsia This process uses separate inlays of wood, ivory, bone, brass, silver, etc., cut to shape, laid on the ground, the outlines traced with a fine point and the appropriate recesses cut in with wood-craving tools.
Integrated Logging Logging operation that segregates and delivers a variety of products to mills and processors that will use them to their greatest potential.
Intensive Forest Management Utilization of a wide variety of silvicultural practices, such as planting, thinning, fertilization, harvesting, and genetic improvement to increase the capability of the forest to produce fiber.
Intergrown Knot One partially or completely Intergrown on one or two faces with the growth rings of the surrounding wood.
Interim Forest A forest that exists or will exist until conversion to a target forest is complete. An interim forest may develop under intensive forest management and may be excellent stocking, but it does not necessarily represent the forest desired at some future time. This is also known as transition forest.
Interior finish. Material used to cover the interior framed areas, or materials of walls and ceilings
Interlocking Yarder Device that allows the main and haul-back drums to be operated together as a single unit to maintain running line tension.
Intermediate Support Spar tree or cable sling located between the head spar and tail spar to which a tree jack is attached to support a multispan skyline.
Intermediate Trees Trees with small, crowded crowns below, but extending into the general canopy level; these trees receive little light from above and none from the side.
Internal Stresses Stresses that exist within an adhesive joint even in the absence of applied external forces.
International 1/4-inch Scale A log scale modification of an earlier rule using a 1/8-inch kerf, based on an analysis of the loss of wood fiber incurred in the conversion of saw logs to lumber. This is one of the few rules that incorporates a basis for dealing with log taper.
International Log Rule A formula rule that allows a 1/2 inch taper from each 4 feet of length and allows for 1/16-inch shrinkage for each inch of board thickness. This rule is used by the USDA Forest Service.
Interphase In wood bonding, a region of finite thickness as a gradient between the bulk adherent and bulk adhesive in which the adhesive penetrates and alters the adherents properties and in which the presence of the adherent influences the chemical and/or physical properties of the adhesive.
Intolerant A tree relatively incapable of developing and growing normally in the shade of, and in competition with, other trees.
Intumesce To expand with heat to provide a low-density film; used in reference to certain fire-retardant coatings.
IPE An exotic hardwood of South America; renowned for its attractive color, density and rigidity.
Iroko Golden-orange to brown in color
Isotropic Exhibiting the same properties in all directions.
IWP Idaho White Pine


J&P Joists and Planks
Jack A device used for suspending a loading-line lead block from a skyline.
Jack rafter. A rafter that spans the distance from the wall plate to a hip, or from a valley to a ridge.
Jackpot An unskilled example or display of logging work. Contemptuous expression applied to an unskilled piece of work in logging, particularly in felling, where several trees are lodged and/or crisscrossed.
Jamb. The side and head lining of a doorway, window, or other opening.
Jammer A lightweight, two-drum yarder usually on a truck with a spar and boom; may be used for both short distance yarding and loading. Frame mounted on a sled or vehicle for loading logs.
Jammer Logging Cable logging system generally restricted to one skidding line and used for winching logs up to 300 feet from the cutting area to a log collection point.
Janka Test A hardness test, usually for wood flooring, the rating is pounds of pressure required to press a steel ball .444 inches in diameter one half way into the wood.
Jig A device used to make special cuts, guide a tool, or aid in woodworking operations.
Jig Saw A power tool that cuts by moving a blade up and down as it is guided through the cut.
Joiner A machine to true the edges of boards usually in preparation for gluing.
Joinery The craft of connecting and securing the separate members of the timber frame to one another by means of specific cuts on the ends and/or sides of the timbers.
Joint Part or the arrangement of the part, where two or more timbers are joined together.
Joint cement. A powder that is usually mixed with water and used for joint treatment in gypsum-wallboard finish. Often called “spackle.”
Joint. The space between the adjacent surfaces of two members or components joined and held together by nails, glue, cement, mortar, or other means.
Jointed (JTD) In lumber manufacture, finger-jointing is most common although sometimes other types of joints may be used.
Joist A piece of lumber two to four inches thick and six inches wide, used horizontally as a support for a ceiling or floor. Also, such a support can be made from aluminum, steel, or other materials.
Joist Hanger A pre-manufactured metal piece typically attached to a ledger or to beam to support a joist. Joist hangers should be galvanized.
Joist. One of a series of parallel beams, usually 2 inches in thickness, used to support floor and ceiling loads, and supported in turn by larger beams, girders, or bearing walls.
Joists and Planks (J&P) The national grading rules contain four grades of structural joists and planks; select structural, No. 1, No. 2, and No. 3. Nominal sizes are 2 to 4 inches thick by 5 inches and wider. The abbreviation (J&P) in generally used to indicate a specific section in the grading rules under which the lumber was graded.
Joystick A hydraulic control lever that can be operated in up to four directions, controlling a number of functions through one hydraulic valve.
JTD Jointed
Juvenile Wood The wood in every tree that forms within its first 10 years or so; usually has undesirable characteristics such as low strength and shrinkage along the grain.


KD Kiln Dried
Kerf The groove left in a board when cut by a saw blade.
KG Blade The blade on a crawler used to clear unwanted vegetation in preparation for planting tree seedlings.
Kickback When a work-piece is thrown back in the opposite direction the cutter is turning.
Kiln In lumber drying, a kiln is a room or building where air circulation, moisture, and temperature are controlled to dry wood.
Kiln Dried Lumber that has been dried in a kiln
Kiln dried lumber. Lumber that has been kiln dried often to a moisture content of 6 to 12 percent. Common varieties of softwood lumber, such as framing lumber are dried to a somewhat higher moisture content.
King Post A central, vertical post extending from the bent plate or girt to the junction of the rafters at roof peak.
Kingwood Variegated colors of rich violet-brown to almost black
Kink A form of warp characterized by abrupt deviation from straightness or flatness due to either localized grain distortion (as around knots) or to deformation by misplaced stickers.
Kip Unit of weight or force equivalent to 1,000 pounds.
Knee Brace A short diagonal timber placed between the horizontal and vertical members of the frame to make them rigid.
Knockdown A design feature that allows a piece of furniture to be easily disassembled by the use of special hardware or joinery.
Knot A branch or limb embedded in a tree and cut through in the process of manufacturing. Knots are classified according to occurrence, quality, and size. In lumber, the size classifications are: Pin knot, one not over ½-inch in diameter; Small, a knot larger then ½-inch but not over ¾-inch; Medium, larger then ¾-inch but not over 1 ½-inch; Large, over 1 ½-inch in diameter.
Knot Cluster Two or more knots grouped together as a unit with the fibers in the wood deflected around the entire unit.
Knot. In lumber, the portion of a branch or limb of a tree that appears on the edge or face of the piece.
Knuckleboom Hydraulically operated loading boom whose mechanical action imitates the human arm.
Kraft Paper Comparatively coarse paper particularly noted for its strength; unbleached grades are used primarily as a wrapping or packaging material.


L Larch
Lacewood When some woods are quarter-swan, a mottled effect is revealed in the section through the medullar rays. In some woods, like maple and elm, the effect is very subtle, but in others it is regular and distinctive. The classic examples are European or London place (Platanus acerifolia) and Roupala (Roupala brasiliensis). These species are often referred to as lacewood.
Lacquers A finish; a clear varnish.
Lag Screw A large screw, usually 4 inches or longer, with a hex head, tuned with a wrench.
Laminate A thin, plastic material used to cover a board. The most common use of laminate is for counter and table tops. It is often referred to by the brand name Formica ®.
Laminated Strand Lumber (LSL) Similar to oriented strand lumber with somewhat longer strands.
Laminated Veneer Lumber (LVL) Structural wood members constructed of veneers laminated to make a “flitch” from which pieces of specific sizes can be trimmed.
Laminated Veneer Lumber (LVL) Structural composite lumber manufactured from veneers laminated into a panel with the grain of all veneer running parallel to each other. The resulting panel is ripped to common lumber dimensions.
Laminated Wood A “piece” of wood built up of plies or layers that have been joined; either with glue or mechanical fastenings. The term is most frequently applied where the plies are too thick to be classified as veneer and when the grain of all plies is parallel.
Land Base Acres of forest land that are actually available for forest management. This involves future trends not only in forest growth but also in deletions from the land base.
Landing A cleared area in the woods to which logs are yarded for loading onto trucks for shipment to a processing plant. This is also known as brow, deck, dock, or ramp.
Landing. A platform between flights of stairs or at the termination of a flight of stairs.
Latewood (Summer Wood) The part of a trees annual growth ring that is formed later in the season.
Latex Paint A paint containing pigments and a stable water suspension of synthetic resins that forms an opaque film through coalescence of the resin during water evaporation and subsequent curing.
Lath A thin, narrow wooden strip, used as a backing for wall plaster or other materials.
Lath. A building material of wood, metal, gypsum, or insulating board that is fastened to the frame of a building to act as a plaster base.
Lathe Checks In rotary cut and sliced veneer, the fractures or checks that develop along the grain of the veneer as the knife peels veneer from the log. The knife side of the veneer where checks occur is called the loose side. The opposite and log side of the veneer where checking usually does not occur is called the tight side.
Lattice A framework of crossed wood made of laths or other thin pieces of wood. Lattice often can be bought pre-made in 4×8 sheets.
Lattice. A framework of crossed wood or metal strips.
LB Lumber
LCL Less than Carload
Leader. See Downspout.
Leave Strip A strip of uncut timber left between cutting units or adjacent to another resource such as a stream. This is also known as a buffer strip, green strip, or streamside management zone.
Ledger A length of a board that is horizontally attached to the side of a house and holds up one edge of a deck.
Ledger strip. A strip of lumber nailed along the bottom of the side of a girder on which joists rest.
Less than Carload (LCL) This term indicates that a railcar is not loaded full, nor does it meet minimum requirements as prescribed by railed tariffs.
Let-in brace. Nominal 1 inch-thick boards applied into notched studs diagonally.
Level An instrument for asserting whether a surface is horizontal, vertical, or at a 45 degree angle; essentially consists of an encased, liquid-filled tube containing an air bubble that moves to a center window when an instrument is set on an even plane.
LF Light Framing
LFVC Loaded fullvisible capacity
LFVC A railroad term to accord light weight lumber shipments the same freight rate consideration as heavier species on higher carload minimum weights. If a car is loaded full, shipper obtains benefit of lowest rate even though minimum weight requirements for lowest rate haven’t been met.
LGR Longer
LGTH Length LIN (Lineal)
Light Framing (LF) The national grading rules contains three grades of light framing; construction, standard and utility. Nominal sizes are 2 to 4 inches thick and 2 to 4 inches wide. The abbreviation (LF) is used to indicate a specific section in the grading rules under which the lumber was graded.
Light Sap Stain A slight difference in color which will not materially impair the appearance of a piece if given a natural finish.
Light. Space in a window sash for a single pane of glass. Also, a pane of glass.
Lignin A complex chemical substance making up approximately 25% of wood substance; interspersed with cellulose in forming the cell wall. Lignin stiffens the cell and functions as a bonding agent between cells; the second most abundant constituent of wood, located in the secondary wall and the middle lamella.
Limbwood The part of the tree above the stump that does not meet the requirement for saw logs or upper stem portions. Includes all live, sound branches to a 4-inch outside back diameter minimum.
Limestone A sedimentary rock composed largely to minerals calcite, and/or aragonite, which are different crystal forms of calcium.
Line Level A level that hangs from a mason’s line; typically used to transfer level elevations from one post to another.
Lineal (LIN) A term referring to length; lineal footage is the total length in feet of a piece or of all pieces of the same width in a shipment. It is used largely for specialty itmes such as mouldings and millwork.
Linear Foot A measurement of the length of a board (i.e. – Three 8-foot-long 2x4s and four 6-foot-long 2x4s both would be described as 24 linear feet of 2x4s).
Linseed Oil This is an amber-colored, fatty oil extracted form the cotyledon and inner coats of the linseed. The raw oil extracted from the seeds by hydraulic pressure is pale in color and practically without taste or order. When boiled or extracted by application of heat and pressure, it is darker, has a bitter taste and an unpleasant odor.
Lintel. A horizontal structural member that supports the load over an opening such as a door or window.
Live Load The amount of weight any structure is designed to support. Most deck designs call for a live load of 60 pounds per square foot.
LNG Lining
Load Area The area found by multiplying the beam spacing by the post spacing to determine the post thickness required by building codes.
Loaded to Full Visible Capacity (LFVC) A railroad term to accord light weight lumber shipments the same freight rate consideration as heavier species on higher carload minimum weights. If a car is loaded full, shipper obtains benefit of lowest rate even though minimum weight requirements for lowest rate haven’t been met.
Loading Jack Rigging suspended from a spar tree guy line immediately above the line of haul and terminating in a loading block.
Lock Set A door lock.
Log 8-foot or longer tree segment.
Log Deck A pile of logs on a wood landing or in a mill yard.
Log Jack A tool used to raise a log from the ground during bucking. Similar to a peavey, but with a flattened steel loop on the underside so when the hook fastens into a log on the ground and the handle is lowered, the log is jacked up and remains elevated.
Log Rule A table intended to show the amounts of lumber that may be sawn from logs of different sizes under various assumed conditions.
Log Scale Measure of the volume of wood in log/logs, usually expressed in board feet and based on various log scaling rules.
Logger A person employed in the production of logs and/or wood from standing timber, also known as a Lumberjack.
Logging Plan Used in the eastern and western regions: layout, on a topographical map, of roads, landings, and setting boundaries of a logging area.
Logging Residues Unused portions of pole timber and saw timber trees killed by land clearing, cultural operations, or timber harvesting.
Logging Setting An area to be logged; a block or strip.
Logging Truck A vehicle used to transport logs. A logging truck consists of a cob, containing the engine and a place for the driver to sit, and a trailer on which logs are placed. The trailer usually has an adjustable carriage in order to accommodate loads of various lengths.
London Dispersion Forces Intermolecular attraction forces between non-polar molecules that result when instantaneous dipoles induce matching dipoles in neighboring molecules.
Long Butt A section cut from the bottom log of a tree and culled because of rot and other defects.
Longitudinal Parallel to the direction of the wood fibers.
Long-Line Skidding At term currently synonymous with skyline skidding.
Long-Span Skidding A cable system capable of skidding logs for 3,000 feet or more.
Longwood Pulpwood 120 inches or more in length.
Longwood Harvesting A timber harvesting method in which harvested trees are moved to the landing either as whole trees or as topped and limbed tree-length logs. At the landing, further processing such a limbing, topping, bucking, chipping, or loading is carried out as necessary.
Lookout. A short wood bracket or cantilever to support an overhang portion of a roof or the like, usually concealed from view
Loose Knot A knot not held in place by growth, shape or position.
Loosened or Raised Grain Consists of a small portion of the wood being loosened or raised but not displaced.
Louver. An opening with a series of horizontal slats so an ranged as to permit ventilation but to exclude rain, sun. light, or vision. See also Attic ventilators.
Low Voltage Lighting Commercially available lighting systems that use a transformer to reduce the needed electrical current. These lighting systems are designed for do-it-yourself applications.
LP Lodgepole Pine
Lumber Logs which have been sawn, planed, and cut to length; a manufacture product derived from a log in a saw mill, or in a sawmill and planing mill. Which when rough shall have been sawed, edged and trimmed at least to the extent of showing saw marks in the wood on the four longitudinal surfaces of each piece for its overall length, and which has not been further manufactured other than by cross-cutting, ripping, resawing, joining crosswise and/or endwise in a flat plane, surfacing with or without end matching and working.
Lumber Ruler A tool resembling a ruler with a handle at one end and a hood at the other which is used to calculate the board footage of a piece of lumber.
Lumber Tally A record of lumber giving the number of boards or pieces by width, thickness, length, grade and species.
Lumber Tally Record of lumber giving the number of boards or pieces by size, grade, and species; often expressed in MBF.
Lumber, boards. Yard lumber less than 2 inches thick and 2 or more inches wide.
Lumber, dimension. Yard lumber from 2 inches to, but not including, 5 inches thick and 2 or more inches wide. Includes joists, rafters, studs, plank, and small timbers.
Lumber, dressed size. The dimension of lumber after shrinking from green dimension and after machining to size or pattern.
Lumber, matched. Lumber that is dressed and shaped on one edge in a grooved pattern and on the other in a tongued pattern.
Lumber, shiplap. Lumber that is edge-dressed to make a close rabbeted or lapped joint.
Lumber, timbers. Yard lumber 5 or more inches in least dimension. Includes beams, stringers, posts, caps, sills, girders, and purlins
Lumber, yard. Lumber of those grades, sizes, and patterns which are generally intended for ordinary construction, such as framework and rough coverage of houses.
Lumber. Lumber is the product of the sawmill and planing mill not further manufactured other than by sawing, resawing, and passing lengthwise through a standard planing machine, crosscutting to length, and matching.
Lumber-Core Plywood Plywood where thin sheets of veneer are glued to a core of narrow boards. Lumber-core plywood differs from regular plywood in that regular plywood is made up of successive layers of alternating grain veneer.
Lumberjack One who works in forest performing a variety of jobs related to the harvesting of timber; most commonly used in the Northeastern United States and eastern Canada. Also known as a logger.
Lumen The cell cavity in wood anatomy.


M Thousand
Macassar Ebony Dark brown to black heartwood
Machinability The relative ease with which a metal can be shaped by various cutting processes.
Machine Bolt A bolt typically configured with a hex head, a nut and a blunt end. It is meant to hold two pieces, usually the support structure by pinning them together; the threads hold only the nut and don’t screw into the wood itself.
Machine Burn Burn marks on the surface of converted wood as a result of poor sawing or machining.
Machine Burn Burn marks on the surface of converted wood as a result of poor sawing or machining.
Machine Rate Cost per unit of time for owning and operating a logging machine or some logging equipment. In accordance with engineering practices, the rate is composed of fixed costs such as depreciation, interest, taxes, and license free, and variable costs including fuel, lubricants, and repairs and replacement of components such as tries and wire rope.
Machine Stress-Rated (MSR Lumber) Lumber that has been evaluated by mechanical stress rating equipment; each piece is nondestructively tested and marked to indicate the modulus of elasticity. MSR lumber is also required to meet certain visual requirements.
Mahogany An expensive, pink to dark reddish brown hardwood. It is a tropical tree of the genus Swietenia.
Main Line In cable yarding, the line used to bring logs to the landing.
Main Line In cable yarding, the line used to bring logs to the landing.
Main Line Block Block on a spar through which the main line runs.
Main Road Road that supports a high level of traffic, usually well built and well designed.
Makore Pick-red to blood red and red-brown heartwood
Mallet A tool like hammer with a wooden, rawhide or rubber head.
Managed Harvest Estimated volume of timber on commercial forest land that could be cut annually for the next ten years while improving tree stocking and bringing about a more even distribution and age classes. Annual managed harvest is considered separate from harvest cuttings and thinnings and is determined by a computer using an area control system that specifies the number of acres to be cut annually.
Managed-Volume Inventory Computation of pertinent data, such as volume or basal area and increment and mortality of stands, to assess silvicultural opportunities.
Man-Hour Unit of work preformed by one man in one hour.
Mantel. The shelf above a fireplace. Also used in referring to the decorative trim around a fireplace opening.
Manufacturer The producing sawmill sawing lumber from logs.
Manufacturer’s Agent A sales representative for a particular sawmill or several non-competitive lumber manufacturers.
Manufacturing Defects Includes all defects or blemishes that are produced in manufacturing, such as chipped grain, loosened grain, raised grain, torn grain, shkips in dressing, hot and miss, variation in sawing, mis-cut lumber, machine burn, machine gouge, mismatching, and insufficient tongue and groove.
Mark To select and indicate, usually with paint, trees to be felled in a logging operation and to be left may also be marked.
Marking Selecting and indicating, by a blaze or paint spot, the trees to be cut or left in a timber cutting operation.
Marlin Spike Iron tool that tapers to a point. This is used to separate strands of rope.
Masonry. Stone, brick, concrete, hollow-tile, concrete block, gypsum block, or other similar building units or materials or a combination of the same, bonded together with mortar to form a wall, pier, buttress, or similar mass
Mason’s Line A string that does not stretch, making it useful to establish horizontal lines when laying out the various heights of a deck.
Mastic A material with adhesive properties, usually used in relatively thick sections, which can be readily applied by extraction, trowel, or spatula.
Mastic. A pasty material used as a cement (as for setting tile) or a protective coating (as for thermal insulation or waterproofing)
Mat A temporary roadway constructed of hardwood lumber.
Mature Timber A stand of trees that has attained an age or size that satisfies the primary economic goal for which it is managed.
MBF Thousand Board Feet.
MBM Thousand (ft.) board measure.
MC Moisture Content.
MDF Medium density fiberboard, very stable underlay for counter tops etc. to be covered with laminate.
Mean Annual Increment (MAI) Total increment growth up to a given age divided by that age.
Meandering Line Survey line at the high-water mark on navigable lakes and streams. This line is where continuous vegetation ends and muddy or sandy shore beings.
Measuring The process of dividing the merchantable tree stem into segments of specified length for the purpose of bucking. Measuring a stand begins when a worker begins dividing the first tree into desired lengths and ends when the last tree has been measured.
Measuring Tape A tape of cloth, paper, plastic, or steel marked off in a linear scale, as of inches or centimeters, for taking measurements.
Mechanical Adhesion Adhesion between surfaces in which the adhesive holds the parts together by interlocking action.
Mechanical Delay Time Cutting with mechanized equipment, such as the carrier-mounted shear of feller-buncher, instead of by hand with a power saw.
Mechanized Logging Logging in which most or all of the hand labor is replaced by machines; requires a large outlay of capital.
Medium Density Fiberboard (MDF) A special type of tempered hardboard characterized by a very fine, smooth finish. MDF is used in cabinet making.
Medium Grain Wood with 4 to 6 rings per inch.
Mensuration In forestry, the measurement of both standing and harvested timber.
Merch Merchantable
Merch Top Merchantable Top
Merchantable Top Smallest utilizable top.
Meristem A tissue capable of active cell division, thereby adding new cells to the plant body.
Metal lath. Sheets of metal that are slit and drawn out to form openings. Used as a plaster base for walls and ceilings and as reinforcing over other forms of plaster base.
Metric Tons Unit of weight equal to 1,000 kilograms. Approximately 2,205 pounds.
MG Mixed Grain
Microbevel An extremely narrow bevel along a cutting edge, which increases the sharpness angle for greater edge durability.
Milk Pain Paint made with milk solids, chemically akin to casein glue, often the original finish on antique furniture.
Mill Run Lumber that is in varying grades and widths.
Millwork Planed and patterned lumber for finish work in buildings, including items such as sash, doors, cornices, panel work, and other items of interior or exterior trim. This does not include flooring, ceilings, or siding.
Millwork. Generally all building materials made of finished wood and manufactured in millwork plants and planing mills are included under the term “millwork.” It includes such items as inside and outside doors, window and doorframes, blinds, porchwork, mantels, panelwork, stairways, moldings, and interior trim. It normally does not include flooring, ceiling, or siding.
Mineral Streak An olive to green-black or brown discoloration of undetermined cause in hardwoods.
Mismatched Material Worked material that does not fit tightly at all points of contact between adjoining pieces or in which the surfaces or adjoining pieces are not in the same plane.
Miter Box An apparatus to guide a saw to make miter joints.
Miter Gauge A tool that slides into a slot on a power tool such as a table saw, router table, band saw, etc. A miter gauge can be adjusted to different angels and is used to slide the stock past the blade.
Miter Joint Pieces that are cut on an angle to make a joint.
Miter joint. The joint of two pieces at an angle that bisects the joining angle. For example, the miter joint at the side and head casing at a door opening is made at a 45° angle.
Miter-And-Spline Joint A joint with two mitered surfaces connected by a spline.
Mixed Car A railroad car loaded with various kinds, sizes and/or species of lumber.
Mixed Grain Lumber may be both vertical and flat grain.
MLDG Moulding
Mobile Capable of being moved from one location to another.
Model Theoretical abstraction, usually capable of mathematical manipulation, used to evaluate a problem or a subject of interest.
Modified Wood Wood processed by chemical treatment, compression, or other means to impart properties quite different from those of the original wood.
Modular Housing A type of housing in which major components are assembled in a factory and then shipped to the building site to be joined with other components to form the finished structure. The components are usually uniform incremental sizes; permitting some flexibility of design while maintaining the structure of individual elements. Sometimes called “prefabricated’ or “prefab” housing by laymen; these terms are avoided by the industry because of negative connotations.
Modulus of Elasticity (MOE) The relationship between the amount a piece deflects and the load causing the deflection determines its stiffness.
Moisture Content (MC) A measure of the amount of water in a piece of lumber.
Moisture content of wood. Weight of the water contained in the wood, usually expressed as a percentage of the weight of the ovendry wood.
Molding (Moulding) A strip of material with a profile cut on the facing edges, used for trimming.
Molding. A wood strip having a coned or projecting surface used for decorative purposes.
Molecular Weight The sum of the atomic weights of the atoms in a molecule.
Molle Circle of twisted strands of wire rope used as a temporary line to connect the eye splices of two lines.
Monkey Wrench A half tool with adjustable jaws for turning nuts of varying sizes.
Mopping Up Act of making a fire safe after it has been controlled by extinguishing or removing burning material along or near a control line.
MOR Modulus of Rupture
Morse Taper The standard for the taper on the shanks of drill chucks, drill bits and lathe centers. The different size tapers are designated by numbers, #1 being the smallest, #3 is common for drill chucks.
Mortality Number or sound wood volume of healthy trees that have died from natural causes during a specified period.
Mortality of Growing Stock Volume of sound wood in live sawn timber and pole timber trees dying annually from natural causes. Natural causes include fire, insect disease, and animal damage; weather and suppression.
Mortality of Saw Timer The net board-foot volume of sawn timber trees dying annually from natural causes.
Mortise A rectangular hole cut into a piece of wood to accept a tenon.
Mortise and Tenon Any joint consisting of a projection (tenon) on the end of one timber and a corresponding slot (mortise) on the other.
Mortise. A slot cut into a board, plank, or timber, usually edgewise, to receive tenon of another board, plank, or timber to form a joint.
Mottling A term used to describe various figuring effects, from subtle lacewood to a more velvety figuring.
Moulding (MLDG) Small shaped lengths of wood used for both interior and exterior trim.
Moulding Stock Developed in the making of other standard grades; each piece is graded on the basis of the percentage of the area suitable for ripping into strips of a given minimum size and quality.
MSR Machine Stress Rated
MTCC Malaysian Timber Certification Council.
Mullion. A vertical bar or divider in the frame between windows, doors, or other openings.
Multilevel Deck A deck that has several discrete areas at different levels. The different levels often are built to conform to a sloping terrain or make a transition from a second story to a ground level.
Multiple Entry A deck that has several discrete areas at different levels. The different levels often are built to conform to a sloping terrain or make a transition from a second story to a ground level.
Multiple-Use Practice of forestry that combines two or more objectives.
Multiple-Use Forestry Concept of forest management that combines two or more objectives, such as production of wood or wood-derivative products, forage and brown for domestic livestock, proper environmental conditions for wildlife, landscape effects, protection against floods and erosion, recreation, and protection of water supplies.
Multiple-Use Management Management of land resources with the objective of achieving optimum yields of products and services from a given area without impairing the productive capacity of the site.
Multispan Skyline A skyline having one or more intermediate supports.
Multistem An operation handling two or more stems at the same time.
Muntin A strip of metal or wood separating and holding panes of glass in a window or door.
Muntin. A small member which divides the glass or openings of sash or doors.
Muskeg Tract of partly forested peat-land supporting mosses, shrubby plants, and scattered trees.


N1E Nose One Edge
Nail Gun A mechanical device for driving nails into an object by the force of compressed air.
Nail Set A short shaft of metal with a narrow blunt point used to set nails below the surface of wood by placing the blunt end on the nail head and striking the other end with a hammer.
Nail Staining Caused when the metal bleeds around the nail hole.
Nanoindentation Hardness A hardness measurement conducted at the nanometer scale. Nanoindentation hardness uses an extremely small indenter of a hard material and specified shape to press into the surface of a specimen with sufficient force to cause deformation.
Natural finish. A transparent finish which does not seriously alter the original color or grain of the natural wood. Natural finishes are usually provided by sealers, oils, varnishes, water-repellent preservatives, and other similar materials.
Natural Regeneration Renewal of a forest achieved either by natural seeding or from the vegetative reproduction of plants on the site.
Naval Stores A term applied to the oils, resins, tars and pitches derived from oleoresin contained in, exuded by, or extracted from tress chiefly of pine species or from the wood of such trees.
NBM Net Board Measure
Net Annual Growth Increase in volume of trees during a specified year. Components of new annual growth include the increment of net volume of trees at the beginning of the specified year that survive to the years end, plus the net volume of trees reaching the minimum size class during the year, minus the volume of trees that died during the year, and minus the net volume of trees that become rough or rotten trees during the year.
Net Annual Growth of Growing Stock Annual change in volume of sound wood in live sawn timber and pole timber trees, plus total volume sound wood in live sawn timber and pole timber trees, plus total volume of trees entering these classes through growth, minus volume losses resulting from natural causes.
Net Annual Growth of Saw Timber Annual change in volume of live sawn timber trees plus total volume of trees reaching saw timber size, minus volume losses resulting from natural causes.
Net Board Measure Content of lumber when calculated from measurements of actual dimensions, including tongue or lap.
Net Scale Actual amount of merchantable wood contained in a log as opposed to the gross scale, which includes defects.
Newel, A post to which the end of a stair railing or balustrade is fastened. Also, any post to which a railing or balustrade is fastened.
Nominal Size The rough-sawn size of a piece of lumber. When purchasing planed lumber, it is sold by its nominal, rough sawn size. Usually expressed in terms of the nearest inch regardless of actual surface, or net sizes (i.e. – 2×4 is the name for a rough cut piece of about 2×4 inches. It is then finished by planning and sometimes sanding it down to its actual dimensions).
Nonbearing wall. A wall supporting no load other than its own weight.
Non-Commercial Species A tree species in which small size, poor form, or inferior quality is typical. These species do not normally develop into trees suitable for conventional forest products.
Non-Piloted Bit A router bit without a guide bearing.
Nonpressure Process Any process of treating wood with a preservative or fire retardant where pressure is not applied.
Northern United States Consists of the following States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont, Delaware, Maryland, New Jersey, New York, Pennsylvania, West Virginia, Michigan, Minnesota, South Dakota, Wisconsin, Illinois, Indiana, Ohio, Iowa, Kansas, Kentucky, Missouri, and Nebraska.
Nosing. The projecting edge of a molding or drip. Usually applied to the projecting molding on the edge of a stair tread.
Notch To make an undercut in a tree, preparatory to felling it in a given direction. This is also known as a box or an undercut.
Notch. A crosswise rabbet at the end of a board.
Number One Top-grade logs, such a number one peeler, or a number-one saw log.


O. C., on center. The measurement of spacing for studs, rafters, joists, and the like in a building from the center of one member to the center of the next.
O. G., or ogee. A molding with a profile in the form of a letter S; having the outline of a reversed curve.
Occasional Pieces Means not more than 10 percent of the pieces in a parcel or shipment.
Off-Highway Truck A truck designed to handle loads exceeding legal highway size and weight restrictions. These trucks are not driven on highways; they are used in logging operations conducted on other types of roads.
Ogee A decorative molding profile with an “S” shape.
Oil Paint A paint containing a suspension of pigments in an organic solvent and a drying oil, modified drying oil, or synthetic polymer that forms an opaque film through a combination of solvent evaporation and curing of the oil or polymer.
Old Growth Biologically a stand of timber that is near its climax; such trees may be 200 years or older. In timber management planning, old growth also refers to timber that is older then the rotation age planned for future forests; this definition may include trees that are 100 years or less.
Oleoresin A solution of resin in an essential oil that occurs in or exudes from many plants, especially softwoods.
On Center A method of measuring distance between two structural members, such a joists, where you measure from the center of one member to the center of the other. It is usually abbreviated O.C.
Open Coat A piece of sandpaper with abrasive particles that are spread out to prevent clogging.
Open-Grained Common classification of painters for woods with large pores, such as oak, ash, chestnut, and walnut. This is also known as ‘coarse texture’.
Open-Side Carriage Skyline carriage that opens on one side allowing it to travel over intermediate support jacks.Skyline carriage that opens on one side allowing it to travel over intermediate support jacks.
Open-Top Van A van that can be loaded from above and is often covered by a tarp or mesh.
Operational Cruise Timber inventory that includes the estimation of timber volumes or other stand information on specific geographic areas for specific purposes, as contrasted with more broadly based estimates for forest-wide planning. Inventory survey of a logging unit for developing logging plans and production budgets. Seedling surveys for regeneration stocking and pre-commercial thinning cruises for stand density are examples of operational cruises. Results from these surveys form the basis for decisions on subsequent activities about the specific geographic areas cruised.
Operations Research A scientific approach to decision making that involves the operations of organizational systems.
Operator Estimated volume of timber on commercial forest land that could be cut annually for the next ten years while improving tree stocking and bringing about a more even distribution and age classes. Annual managed harvest is considered separate from harvest cuttings and thinnings and is determined by a computer using an area control system that specifies the number of acres to be cut annually.
Optimum Road Spacing The distance between parallel roads that gives the lowest combined cost of skidding and road construction costs per unit of log volume.
Orbital Sander An electric sander that moves the abrasive in an elliptical pattern.
Oriented Strand Board (OSB) A structural panel made of narrow strands of fiber oriented lengthwise and crosswise in layers, with a resin binder. Depending on the resin used, OSB can be suitable for exterior or interior applications.
Oriented Strand Lumber (OSL) Structural composite lumber made from wood strand elements similar to those used in oriented strand board. The strands are oriented primarily along the length of the member.
Orthotropic Refers to having unique and independent properties in three mutually orthogonal planes of symmetry; longitudinal, radial, and tangential.
Outfeed The side of a power tool where the board exits.
Outrigger. An extension of a rafter beyond the wall line. Usually a smaller member nailed to a larger rafter to form a cornice or roof overhang.
Outriggers Stabilizers that are generally found on Knuckleboom loaders or mobile chippers.
Oven-Dried Weight The weight of a piece of lumber that has been dried, under high temperatures, in an oven until it is devoid of all water. This is used to calculate the moisture content of wood.
Oven-Dry Wood Wood completely dried until it is without any moisture content.
Over Run The difference between the log scale of a shipment of timber and the volume of the actual lumber obtained from it.
Over-All Dimensions The measurements-of thickness, width, or length-of a piece of lumber which are used to compute the space occupied.
Overlay A thin layer of paper, plastic film, metal foil, or other materials bonded to one or both faces of panel products or to lumber to provide a protective or decorative face or a base for painting.
Over-Mature Point at which timber has begun to lessen in commercial value because of size, age, decay or other factors. Many trees in a virgin or old growth stand are over-matured and are, in fact, dying of old age.
Over-Story Layer of foliage in a forest canopy including the trees in a timber stand. Tall mature trees that rise above the shorter immature understory trees.
Over-Story Removal Any silvicultural treatment with the desired end result being the removal of the over-story component from the growing stock of a multistoried stand. Examples are outright harvest, girdling, and simply felling the over-story.
Oysters A few woods are cut into oysters, a cross-section of end grain either at right angles to the grain or at an oblique angle.


P&T Posts and Timbers
Pacific Coast States Alaska, Washington, Oregon, California, and Hawaii.
PAD Partly Air Dried
Paint Any pigmented liquid or mastic composition designed for application to a substrate in a thin layer that converts to an opaque solid film after application.
Paint Brush A brush used for applying paint.
Paint. A combination of pigments with suitable thinners or oils to provide decorative and protective coatings.
Pallet A portable platform used as a base for stacking, storing, and transporting goods in a unit.
Palm Nailer (Push Nailer/Brad Nailer) A palm held, spring loaded tool with a barrel for holding fine brads and pins. A fine hobby nail or brad is dropped down the barrel of the tool and the tool is then held against the wood and pushed.
Pan Large, flat upward-curving metal plate on which log ends or pallets are placed to make skidding easier and prevents digging in and rutting.
Panel In house construction, a thin flat piece of wood, ply. wood, or similar material, framed by stiles and rails as in a door or fitted into grooves of thicker material with molded edges for decorative wall treatment.
Panel Product Any variety of wood products, such as hardboard, oriented strand board, particleboard, plywood, or waferboard, sold in sheets or panels. Although sizes vary, a standard size for most panel products is 4×8 feet.
Paper Wrapped (PW) Lumber strapped into units and wrapped in weather resistant material prior to shipment.
Paper, building. A general term for papers, felts, and similar sheet materials used in buildings without reference to their properties or uses.
Paper, sheathing. A building material, generally paper or felt, used in wall and roof construction as a protection against the passage of air and sometimes moisture.
Paperboard The distinction between paper and paperboard is not sharp, but broadly speaking, the thicker, heavier, and more rigid grades of paper are called paperboard.
PARA Paragraph PART — Partition
Parallel Strand Lumber (PSL) Structural composite lumber made from high aspect ratio wood strand elements manufactured from veneer oriented primarily along the length of the member. It is manufactured in billets and cut to lumber dimensions.
Parenchyma Short cells having simple pits and functioning primarily in the metabolism and storage of plant food materials. They remain alive longer than the tracheids, fibers, and vessel elements, sometimes for many years. There are two kids of parenchyma cells; vertical strands, also known as axial parenchyma, and those in horizontal series, also know as ray parenchyma.
Parent Tree Any tree whose seeds are used to product progeny for use in genetic experimentation. Usually the parent tree is selected because it displays characteristics either interesting from a research standpoint or desirable in an operational forest management program.
Partial Cut A logging area in which only part of the trees are felled and bucked, as opposed to clear cut.
Particleboard A type of manufactured plywood that is made from ground up and glued scrap wood. Particle board is very dense, heavy and flat.
Particleboard Core Plywood Plywood that is made by gluing a thin layer of veneer to a piece of particleboard.
Particles The aggregate component of particleboard manufactured by mechanical means from wood.
Parting stop or strip. A small wood piece used in the side and head jambs of double-hung windows to separate upper and lower sash.
Partition. A wall that subdivides spaces within any story of a building.
Partly Air Dried (PAD) Seasoned to some extent by exposure to the atmosphere, but still considered green or unseasoned.
Pass Block A light-weight block hung at the top of the spar tree and used to lift the bull block and other gear in rigging the tree.
PAT Pattern
Pay-As-Cut Timber purchased based on a dollar amount for a certain amount/volume of wood, such as dollars per MBF. Payment is made only as timber is cut and transported.
Payload The gross weight of a loaded vehicle minus the weight of the vehicle itself.
Payout To unreel cable.
Peat Generally, unconsolidated material that consists mainly of un-decomposed, or only slightly decomposed, organic matter accumulated under conditions of excessive moisture. More specifically, a layer of organic material containing plant residues that may show little, if any, morphological change and that have accumulated as a result of submergence in water or through being in a very wet environment.
Peavey A stout wooden lever, fitted with a strong, sharp spike used for rolling logs.
Peck Pockets or areas of disintegrated wood caused by advanced stages of localized decay in the living tree; it is usually associated with cypress and incense cedar; there is no further development of peck once the tree is felled.
Peel To convert a log into veneer by rotary cutting.
Peeler A high-grade log from which veneer is peeled, on a lathe, for the production of plywood. Peelers are most frequently from old-growth trees. The resulting veneer is usually clear and used in sanded plywood.
PEFC Program for the Endorsement of Forest Certification Schemes, which was formally known as the Pan European Forest Certification Scheme.
Peg A hardwood dowel usually ranging from 5/8 of an inch to 2 inches in diameter.
Pencil Stock Made from Incense Cedar, pencil stock is graded for the percentage of clear pencil squares that may be obtained from a piece by ripping and cross cutting.
Pendant An ornamental termination to the low end of a hammer post, king post, queen post, etc.
Penny. As applied to nails, it originally indicated the price per hundred. The term now series as a measure of nail length and is abbreviated by the letter d.
Pennyweight A system of measuring the size of a nail. Originally derived from a unit of weight, pennyweight is represented by the letter “d”.
Periodic Annual Increment (PAI) Mean annual growth or increase in volume during a specific period of time.
Perm. A measure of water vapor movement through a material (grains per square foot per hour per inch of mercury difference in vapor pressure).
PET Precision End Trimmed
Phillips Head A type of screw head requiring a driver in the shape of +.
Phloem The inner part of a trees bark that delivers water and other nutrients.
Photosynthesis The process that plants use to synthesize nutrients from water and minerals, using light.
Phylum A class of a group of plants. Phylum is a botanical term used by botanists to classify plants.
Picket A sharpened or pointed pale, post, or stake usually used as fencing.
Piece Rate Payment for labor where income is related to output.
Piedmont Located or formed at the base of a mountain range; an example would be piedmont terrace. Area, plain, slope, glacier, or other feature at the base of a mountain, such as a foothill or bajada. In the United States, the plateau extending from New Jersey to Alabama and lying east of the Appalachian Mountains is considered a piedmont.
Pier A masonry post. Piers often serve as above-gate footings for posts and often are made of pre-cast concrete.
Pier. A column of masonry, usually rectangular in horizontal cross section, used to support other structural members.
Pigment. A powdered solid in suitable degree of subdivision for use in paint or enamel.
Pike A long pole with a pointed steel head used in raising bents, also called a barn pole.
Piling Round timber of any required size or length, usually used with smaller end in the ground.
Pilot Bit A router bit fitted with bearing above the cutter which rides on the edge of a board or template, keeping the bit a fixed distance from the edge.
Pin Hole From any cause approximately 1/16” in diameter.
Pin Knot One knot over ½” in diameter.
Pin Router A router that is fixed above a table with its bit point down. A pin in the table is aligned with the bit and used to route the workplace.
Pine Any evergreen tree of the genus Pinus, native to northern temperate regions. Trees with needle shaped sprees growing in clusters.
Pintle Hook Hooking device normally found on the rear of a piece of equipment and used to pull or attach a cable or trailer.
Pit A colloquialism for a landing, also known as a deck or ramp.
Pitch The number of teeth on a saw blade per inch.
Pitch Pocket A pocket of resinous sap confined within the grain of many conifers.
Pitch pocket. An opening extending parallel to the annual rings of growth, that usually contains, or has contained, either solid or liquid pitch
Pitch Seam Shake or check which is filled with pitch.
Pitch Streak A well-defined accumulation of pitch in the wood cells in a more or less regular streak.
Pitch. The incline slope of a roof or the ratio of the total rise to the total width of a house, i.e., an 8-foot rise and 24-foot width is a one-third pitch roof. Roof slope is expressed in the inches of rise per foot of run.
Pith A soft core in the center of a tree trunk.
Pith Fleck A narrow streak, resembling pith on the surface of a piece, resulting from burrowing of larvae in the growing tissues of the tree.
Pith. The small, soft core at the original center of a tree around which wood formation takes place.
Plain and Profile A drawing showing both horizontal (plan) and vertical (profile) delineation of the road survey.
Plain-Sawn Lumber A method of sawing lumber, where the log is cut tangential to the growth rings.
Planimeter An instrument used to mechanically measure an area by tracing the perimeter on a place surface. This is typically used to estimate the size of an area from scale maps.
Planing Mill Products Surfaced or planed lumber; products worked to pattern, such as flooring, ceiling, and siding.
Plank A piece of lumber, from 2 but not including 5 inches thick, generally used with wide face horizontal.
Plant The major horizontal timber which runs from one end of the frame to the other and supports the base of the rafters.
Plant Byproducts Wood products, such as pulpwood chips, obtained incidental to the production of other manufactured products.
Plant Residues Wood material from manufacturing plants not utilized as a product.
Plantation A forest stand regenerated artificially either by sowing or planting.
Planting An artificial regeneration method in which a new stand of trees is established by restocking the area with tree seedlings.
Plaster grounds. Strips of wood used as guides or strike off edges around window and door openings and at base of walls.
Plasticizing Wood Softening wood by hot water, steam, or chemical treatment to increase its moldability.
Plate Joint A butt joint that is reinforced with a football shaped “biscuit”. The biscuits are usually made from compressed pieces of wood, usually birch. When a biscuit comes into contact with glue in the joint, it swells creating a tighter joint.
Plate. Sill plate: a horizontal member anchored to a masonry wall. Sole plate: bottom horizontal member of a frame wall. Top plate: top horizontal member of a frame wall supporting ceiling joists, rafters, or other members.
PLIB Pacific Lumber Inspection Bureau
Plough. To cut a lengthwise groove in a board or plank.
Plumb A term used to describe something that is perfectly perpendicular to the earth relative to gravity. A plumb bob on the end of a string will give you a line that is plumb or straight up and down.
Plumb Bob A usually conical metal weight attached to the end of a plumb line.
Plumb. Exactly perpendicular; vertical.
Plunge Cut Starting a cut in the center of a log using the tip of the chain saw blade. This is also known as boring.
Plunge Router A router mounted on a spring loaded base. The router can be turned on and plunged down into the work piece.
Ply A term to denote the number of thicknesses or layers of roofing felt, veneer in plywood, or layers in built-up materials, in any finished piece of such material.
Plywood A flat panel made up of a number of thin sheets, or veneers, of wood in which the grain direction of each ply, or layer, is at right angels to the one adjacent to it. The veneer sheets are united, and under pressure, via a bonding agent.
Plywood. A piece of wood made of three or more layers of veneer joined with glue, and usually laid with the grain of adjoining plies at right angles. Almost always an odd number of plies are used to provide balanced construction.
Pneumatic Nailer A nail gun activated by air pressure.
Pocket A well-defined opening between the rings of annual growth, usually containing pitch or bark.
Pocket Hole A hole drilled on an angle with a step bit to make a butt joint. The larger hole is for the screw head to enter, and the smaller hole is for the shank.
Pocket Rot Advanced decay which appears in the form of a hole, pocket or area of soft rot usually surrounded by apparently sound wood.
Pogo Stick A stand used to hold the air hose and electrical connections mounted behind the cab on a truck tractor. This is also known as a hitchhiker.
Polar Characteristics of a molecule in which the positive and negative electrical charges are permanently separated, as opposed to non-polar molecules in which the charges coincide.
Pole Young tree at least 4 inches and less than 8 to 12 inches in D.B.H.
Pole Size Trees from 5 to 11 inches in D.B.H.
Pole Timber Arbitrary term for small sawn timber trees. Generally, trees 12 to 18 inches in D.B.H. This is also known as small saw timber.
Polymer A compound formed by the reaction of simple molecules having functional groups that permit their combination to proceed to high molecular weights under suitable conditions.
Polymerization A chemical reaction in which the molecules of a monometer are linked together to form large molecules whose molecular weight is a multiple of that of the original substance.
Pond Value Market price of logs delivered to a wet site, log pond, or tidewater.
Poplar Creamy-white to grey in color
Pores. Wood cells of comparatively large diameter that have open ends and are set one above the other to form continuous tubes. The openings of the vessels on the surface of a piece of wood are referred to as pores.
Porous Wood Wood with larger than normal pores and vessels.
Portable Something that can be picked up and carried from one location to another.
Post Upright or vertical timbers erected within the frame that provide structural support of the members above.
Post Anchor A metal piece attached to or imbedded in the footing that attaches the post to the footing and keeps the post from being exposed to moisture in the ground.
Post Cap A small piece of wood attached to the top of the post to cover the posts wood grain and protect the post from the weather.
Post Cure A treatment applied to an adhesive assembly following the initial cute, to complete cure, or to modify specific properties.
Posts and Timbers Large pieces (nominal dimensions 5” by 5” and larger, width not more than 2” greater than thickness) of square or approximately square cross section graded primarily for use as posts or columns.
Potential Yield The estimated maximum sustained yield cutting level (stated for a period of time such as a year or decade) attainable with intensive forestry; considers productivity of the land, conventional logging technology, standard cultural treatments, and interrelationships with other resource uses and the environmental. Excluded in the estimates are the effects of fertilization, genetic improvement, and irrigation, which have not yet been proven to be economically feasible over large portions of the country.
Power Shift Transmissions that can be shifted while transmitting full engine power to the tracks or wheels.
PP Ponderosa Pine.
Precision End Trimmed (PET) Lumber is trimmed square and smooth on both ends to uniform length.
Pre-Commercial Thinning Cutting trees from a young stand so that the remaining trees will have more room to grow to marketable size. Trees cut in a pre-commercial thinning have no commercial value and normally none of the felled trees are removed for utilization. The primary intent is the improve growth potential for the trees left after thinnings.
Precure Condition of too much cure, set, or solvent loss of the adhesive before pressure is applied resulting in inadequate flow, transfer, and bonding.
Prehauling Moving pulpwood from a stump site to a truck loading site by carrying it off the ground. This is also known as forwarding.
Preload To circle several logs with binders so the entire unit can be hauled as one log.
Prelog To remove small understory trees, windfalls, or special products such as poles or pilings from a stand ahead of the main logging to prevent breakage.
Pre-logging Cutting specified high-valued wood products such as poles and pilings before cutting the remainder of the trees.
Prescribed Burning Deliberate use of fire under conditions where the area to be burned is predetermined and the intensity of the fire is controlled.
Preservative Any substance that, for a reasonable length of time, will prevent the action of wood-destroying fungi, bores or various kinds, and similar destructive life when the wood has been properly coated or impregnated with it.
Preservative Any substance applied to wood that helps it resist decay, harmful insects, or rotting.
Preservative. Any substance that, for a reasonable length of time, will prevent the action of wood-destroying fungi, borers of various kinds, and similar destructive agents when the wood has been properly coated or impregnated with it.
Pressure Pricess Any process of treating wood in a closed container whereby the preservative or fire retardant is forced into the wood under pressure greater than one atmosphere.
Pressure-Treating A process of impregnating lumber or other wood products with various chemicals, such as preservatives and fire-retardants, by forcing the chemicals into the structure of the wood using high pressure.
Preventive Maintenance Maintenance measures taken in advance to avoid breakdowns.
Primary Logging Road Road designed and maintained for a high level of use. Typically an all-weather gravel road that is used in a permanent road system.
Primary Transportation Movement of a felled tree from the stump to a landing.
Primary Wood This is the wood that is on the main or primary surfaces of a piece of furniture. These are the premium or money woods of the cabinet.
Prime Log A log that is a given size and free from defects.
Primer. The first coat of paint in a paint job that consists of two or more coats; also the paint used for such a first coat.
Principle Rafters A pair of inclined timbers that are framed into a bend and used with either purlins or secondary rafters or alone.
Priority Sequence The order in which items are to be yarded.
Producer An independent operator who produces and delivers pulpwood to a deal or pulpwood company.
Productive Machine Hour (PMH) Time during scheduled operating hours when a machine performs it’s designated function (time exclusive of such things as machine transport, operational or mechanical delays, and servicing or repair).
Program for the Endorsement of Forest Certification (PEFC) Schemes An organization that was developed to address the issues of the multitude of certification programs with competing standards and serves as an endorsement system that provides international recognition for national forest certification programs.
Proud To protrude above the surface so it is sticking out a bit.
Pruning Removal of live or dead branches from standing trees, usually the lower branches of young trees and of multiple leaders or shoots in plantation trees – for the improvement of the tree or its timber. Cutting away of superfluous growth, including roots, from any plant to improve its development.
Psychrometer An instrument for measuring the amount of water vapor in the atmosphere.
PT Pressure Treated
Pulp Mechanically ground or chemically digested wood used in manufacturing paper and allied products.
Pulp Hook A curved steel hook with a wooden cross handle; used in handling pulpwood.
Pulp Log A log that does not meet the one-third merchantability standard for a sawn log but contains a minimum of 50-percent sound wood fiber by volume.
Pulp Mill A mill that converts pulpwood to wood pulp.
Pulp Trees Small trees and saplings that will be ground to produce paper. Lumber farmers often over-plant their acreage and remove smaller trees for pulp as the crop matures.
Pulpwood Round wood used as a source of wood fiber in a pulp mill. Wood cut or prepared primarily for wood pulp and subsequent manufacture into paper, fiberboard, or other products, depends largely on the species cut and the pulping process.
Pulpwood Dealer The middleman who buys pulpwood from the producer and sells it to the pulp mill company or acts as a commission broker for the company in producing pulpwood.
Purlin A horizontal member of the roof frame which runs between rafters.
Purnice A fine, abrasive powder that is made from volcanic ash. Pumice is used with a felt block in woodworking to rub out (polish) a finish.
Purpleheart Deep-purple violet when freshly cut Straight grained, sometimes interlocked
Push Stick A tool used that is to safely push a board through a table saw or other power tool.
Putty. A type of cement usually made of whiting and boiled linseed oil, beaten or kneaded to the consistency of dough, and used in sealing glass in sash, filling small holes and crevices in wood, and for similar purposes.
PW Paper Wrapped


Quarter round. A small molding that has the cross section of a quarter circle.
Quarter-Sawn A method of cutting lumber where the annual rings are relatively perpendicular to the face of the board. Quarter-sawn lumber tends to be more dimensionally stable then other forms of lumber, such as plane-sawn.
Quarter-Sheet Sander A vibrating sander that uses ¼ size piece of sand paper. It is not an aggressive sander and removes very little material. Optimal for finishing flat surfaces.
Queen Posts A pair of vertical posts of a roof truss standing on the bent or girt and supporting the rafters or collar tie.


R/L (RL) Random Lengths
R/S Resawn
R/W (RW) Random Widths
Rabbet. A rectangular longitudinal groove cut in the corner edge of a board or plank.
Rack and Pinion A system using two gears, one round, and one flat, to move a part. An example would be a drill press; a round gear connected to a handle works with a flat gear on the column to raise and lower the table.
Radial Coincident with a radius from the axis of the tree or log to the circumference; in a round timber or piece of lumber, a line or surface extending outward from the heart-center; a radial surface is always edge-grain.
Radial Arm Saw A circular saw that runs on an overhead track; the track mechanism swings in relation to the table to make miter cuts.
Radial Drill Press A drill press with the head mounted on a tube which is laterally and vertically adjustable. This type gives greater throat clearance but is not as solid as a conventional drill press so run out can be a problem.
Radial Shrinkage Shrinkage in a piece of lumber that occurs across the growth rings as it begins to dry.
Radiant heating. A method of heating, usually consisting of a forced hot water system with pipes placed in the floor, wall, or ceiling; or with electrically heated panels.
Rafter The sloping main line of the roof frame.
Rafter, hip. A rafter that forms the intersection of an external roof angle.
Rafter, valley. A rafter that forms the intersection of an internal roof angle. The valley rafter is normally made of double 2-inch-thick members.
Rafter. One of a series of structural members of a roof designed to support roof loads. The rafters of a flat roof are sometimes called roof joists.
Rail A horizontal board that runs along the underside of a table; the horizontal part of a raised panel door.
Rail Post A vertical structural support for the railing, sometimes also supporting the deck itself and extending down to a footing. Rail posts are thicker than balusters and are attached with bolts to the joists or beams.
Rail. Cross members of panel doors or of a sash. Also the upper and lower members of a balustrade or staircase extending from one vertical support, such as a post, to another.
Railroad Tie A piece of industrial lumber used to support rails on a roadbed. In Britain and other countries it’s known as a “sleeper”.
Raised Grain The roughened condition of sanded wood when the hard latewood rises above the soft earlywood when moisture is applied.
Raised Panel A piece of wood that is the center of a frame and panel assembly.
Rake The angle at which the leading edge of the teeth are cut on a saw blade.
Rake. Trim members that run parallel to the roof slope and form the finish between the wall and a gable roof extension.
Raker A tooth set that has a uniform set angle and a three tooth set sequence of left, right, and straight.
Ram Set Gum A nail gun used in construction and manufacturing to join materials to hard substances such as steel and concrete.
Random Lengths Lumber of various lengths, usually in even two-foot increments. Lumber offered as random-lengths will contain a variety of lengths which can vary greatly between manufacturers and species. A random-length loading is presumed to contain a fir representation of the lengths being produced by a specific manufacturer.
Rasp A long and flat steel tool with raised teeth for shaping wood; some rounded on one side.
Ratchet A generic term used to describe certain tool movements, such as the cone-to-slip engagement on permanent packers or plugs.
Rate of Growth The speed at which a tree increases in size. This may be measured radically in the trunk, or in the dimension of the crown or other tree part. One unit of measure in wood is in number of annual growth rings per inch.
Raw linseed oil. The crude product processed from flaxseed and usually without much subsequent treatment.
Ray A ribbon like figure caused by the strands of cells which extend across the grain in quarter-sawn lumber.
RC Red Cedar
RDM Random
Reach A wooden or metal structural member connecting a logging trailer to a truck tractor.
Reaction Wood Abnormal wood tissue that was formerly in a leaning tree. Reaction wood is very unstable and extremely prone to warping and cupping when sawn into lumber. This wood has distinctive anatomical and physical characteristics. This characteristic is typical in parts of leaning or crooked stems and in branches; it tends to restore to the original position of the branch or stem if this has been disturbed. This is also known as tension wood.
Reciprocating Saw A portable power saw with a reciprocating blade. Can be used with a variety of blades depending on the application and kind of cut; generally has a plate that rides on the surface that is being cut.
Red Oak Pinkish with a red tinge mostly straight grained
Redwood An exceptionally large Californian conifer, Sequoias semervirens, which yields red wood. This is a hot favorite as a decking timber because of the natural decay resistant qualities and beautiful tones.
Reflective insulation. Sheet material with one or both sun faces of comparatively low heat emissivity, such as aluminum foil. When used in building construction the surfaces face air spaces, reducing the radiation across the air space.
REG Regular
Regeneration Renewal of a tree crop, either by natural or artificial means.
Regression A statistical technique used to evaluate relationships among variables.
Reinforcing. Steel rods or metal fabric placed in concrete slabs, beams, or columns to increase their strength.
Relative Humidity The amount of moisture in the air that is measured as a percentage of the total amount of moisture the air can hold at a particular temperature. This is known as relative humidity. The ideal relative humidity for a home is between 35% and 45%. Too much above or below these levels can lead to problems occurring.
Relative humidity. The amount of water vapor in the atmosphere, expressed as a percentage of the maximum quantity that could be present at a given temperature. (The actual amount of water vapor that can be held in space increases with the temperature.)
Reload To transfer logs from one mode of transportation to another or between vehicles.
Re-log To salvage small timber, culls, and other residuals following the main logging operation.
Remote Deck A freestanding platform located away from the house, typically placed for a good view.
Residual Stand Trees remaining in an area after the cutting operation has been completed.
Residual Value The actual or assumed value of a machine after it has been fully depreciated.
Residuals Trees remaining after an intermediate or partial cutting of tree crops or stands. In general, residuals are by products of an operation. Examples are chips from lumber production and hog fuel from any wood processing operation. This is also known as waste.
Residue Wood or bark that is left after a manufacturing process.
Resilience The property where a strained body gives up its stored energy on the removal of the deforming force.
Resin An organic material that has an indefinite and often high molecular weight, exhibits a tendency to flow when subjected to stress.
Resin Ducts Intercellular passages that contain and transmit resinous materials.
Resorcinol Glue. A glue that ishigh in both wet and dry strength and resistant to high temperatures. It is used for gluing lumber or assembly joints that must withstand severe service conditions.
Retention by Assay The determination of a preservative retention in a specific zone of treated wood by extraction or analysis of specified samples.
RGH Rough
Ribbon (Girt). Normally a 1- by 4-inch board let into the studs horizontally to support ceiling or second-floor joists.
Rick A pile of evenly stacked cordwood, stave, bolts, or other short-length wood.
Ridge Beam A horizontal timber to which the tops of rafters are fastened. This is also called a ridge board or a roof tree.
Ridge board. The board placed on edge at the ridge of the roof into which the upper ends of the rafters are fastened.
Ridge Pole A horizontal timber which connects rafter pairs at the peak.
Ridge Purlin The beams connecting rafter to rafter at the apex.
Ridge. The horizontal line at the junction of the top edges of two sloping roof surfaces.
Rift Lumber Diagonally grained lumber.
Rig To install the blocks and lines used in a cable logging system.
Rigging Cables, blocks, and other equipment used in yarding logs.
Right-Of-Way A strip of land on which a road is to be constructed.
Ring-Rot A circular rot in a log. Any rot localized mainly in the springwood of the growth rings, giving a concentric pattern of decayed wood in the cross section of a tree or log.
Rink-Shank Nail A nail with grooves and ridges around the shank to prevent the nail from popping out of the wood as the wood contracts and expands because of changes in moisture and temperature.
Riparian Right A right of someone owning land located on the bank of a natural watercourse, such as a river, lake, or tidewater, to access or use the shore, bed, or water.
Rip-Cut (Ripping) A cut made parallel to the grain of a board.
Ripple Marks Fine horizontal striations visible on the tangential longitudinal surfaces of certain wood. Due to the stories arrangement of the rays or of the axial elements or of both.
Riprap Rough stones of various sizes placed compactly or irregularly on the ground surface to prevent scouring by water or debris.
RIS Redwood Inspection Service
Rise The vertical distance from one stair tread to another.
Rise. In stairs, the vertical height of a step or flight of stairs.
Riser The vertical piece between two stair steps.
Riser. Each of the vertical boards closing the spaces between the treads of stairways.
Robertson Head A screw head requiring a driver with a square tip. This is also referred to as a socket head.
Roll roofing.. Roofing material, composed of fiber and satin rated with asphalt, that is supplied in 36-inch wide rolls with 108 square feet of material. Weights are generally 45 to 90 pounds per roll.
Roller A roller that has an absorbent surface used for spreading paint.
Roof sheathing. The boards or sheet material fastened to the roof rafters on which the shingle or other roof covering is laid.
Roof Truss An engineered building component that supports the roof in place of rafters. Roof trusses are constructed in a triangular shape with a number of interconnected pieces that spread a load evenly across the truss.
Rop Siding (D/S; DS) A lumber pattern with lap or tongue and groove joints.
ROPS Roll-over protective structures that protect the operator if a machine overturns.
Rosser A machine that peels bark using knives.
Rotary Planar A power hand tool with rotating blades that smoothes the surface of material.
Rotary-Cut Veneer Veneer which was cut from a log in one long sheet. Rotary cut veneer is cut from a log like a roll of paper towels.
Rotation Period of years between establishment of a stand of timber and the time when it is considered ready for final harvest and regeneration. The planned number of years between the regeneration of a timber stand and its final cutting.
Rough Cut Lumber that has not been dressed (surfaced) but which has been sawn, edged, and trimmed to at least show saw marks in the wood on the four longitudinal surfaces on each piece for its overall length.
Rough Lumber Lumber which has not been dressed or surfaced but has been sawn, edged, and trimmed.
Rough-Edge Lumber Boards having attached bark on both edges.
Rough-Sawn Lumber that is either green or dried that has not been dressed (planed).
Round Wood A length of cut tree generally having a round cross-section, such as a log or bolt.
Round Wood Products Logs, bolts, or other round sections cut from trees for industrial or consumer use.
Router A high speed motor with handles and an adjustable base with a collet that accepts profile bits to cut dados, rabbets, and shapes.
Rub Bearing A ball bearing rub collar near the top or bottom of a spindle shaper that is used to keep the work piece a fixed distance away from the cutters.
Rub Tree A tree used as a fender or pivot to protect the remaining stand during yarding.
Rubber-emulsion paint. Paint, the vehicle of which consists of rubber or synthetic rubber dispersed in fine droplets in water.
Rule Joint A joinery method used in drop left tables where the tabletop has a convex profile and the left has a concave cut. The two pieces are joined by a hinge.
Run The horizontal distance from one stair riser to another, the depth of a stair step.
Run. In stairs, the net width of a step or the horizontal distance covered by a flight of stairs.
Running Line A moving cable
Running Skyline A system of two or more suspended moving lines, generally referred to as main lines and haul-back lines. Will provide lift and travel to the load carrier when tension is properly applied.
Run-Out The amount of wobble in a shaper or router.
RW/L Random widths and random lengths.
RWD Redwood


S1S Surfaced one face
S2S Surfaced two faces
S2S1E Surfaced two sides, one edge
S3S Surfaced two faces and straight line ripped one edge
S4S Surfaced two faces and straight line ripped two edges
Sacrification Shallow loosening of the soil surface.
Saddle. Two sloping surfaces meeting in a horizontal ridge, used between the back side of a chimney, or other vertical surface, and a sloping roof.
Safety Guy A line rigged under the bull block to take it to the ground if the holding straps break.
Safety Swede A lever used to tighten binders on loaded logging trucks.
Sag Slack in a cable, particularly in a skyline.
Salvage Logging A cleanup operation, generally with a small crew and light equipment, which collects merchantable material too small to be handled economically with big equipment. Salvaging timber damaged by wind, insect, fire, ice, or other natural causes.
Sand Bolster Part of a landing gear that rests on the ground, across and between the two upright portions.
Sand float finish. Lime mixed with sand, resulting in a textured finish.
Santos Mahogany Range of colors between light orange to a dark reddish-purple brown
Sap The water in a tree which is rich in minerals and nutrients.
Sapling Young tree less than 4 inches in D.B.H. The minimum diameter or saplings is usually, although not always, placed at 2 inches.
Sapwood The new wood in a tree that lies between the bark and the heartwood. Sapwood is usually lighter in color and becomes heartwood as the tree ages.
Sapwood. The outer zone of wood, next to the bark. In the living tree it contains some living cells (the heartwood contains none), as well as dead and dying cells. In most species, it is lighter colored than the heartwood. In all species, it is lacking in decay resistance.
Sash A frame structure, normally glazed, that is hung or fixed in a frame set in an opening.
Sash balance. A device, usually operated by a spring or tensioned weatherstripping designed to counterbalance double-hung window sash.
Sash. A single light frame containing one or more lights of glass.
Saturated felt. A felt which is impregnated with tar or asphalt.
Saw Kerf Grooves or notches that are made in cutting with a saw.
Saw Timber Trees suitable for production of saw logs.
Sawhorse A trestle usually used in pairs to hold wood for cutting.
Sawing A basic, cutting process that uses a blade set with a series of teeth on its edge to cut a narrow opening in a work piece. Sawing may be used to produce slots or grooves or to separate the work piece into two pieces.
Sawlog Portion That part of the bole of saw timber trees between the stump and the saw log top.
Sawlogs Logs meeting minimum regional standards of diameter, length, and defect. Logs must be at least eight feet long, have a minimum diameter inside bark of six inches for softwoods and eight inches for hardwoods, and maximum defect as specified by regional standards.
Sawzall A brand of reciprocating saw manufactured by the Milwaukee Electric Tool Company.
Scaffold A temporary platform either supported from below or suspended from above, on which workers sit or stand while performing tasks at heights above the ground.
Scale ‘lb’ measure the weight or volume of a log or load of logs.
Scaling Determination of the gross and net volume of logs using the customary commercial volumetric units for the product involved.
Scalping Removing small plants and duff or ashes from around the spot where a tree seedling will be planted. This is usually done by hand rather than by machine.
Scarf Joint A joint used to splice two timbers end to end.
Schedule Maching Hour Time in which a machine is intended to be operated and has an operator scheduled.
Schoolmarm A tree that initially had a single trunk that later split into two separate trunks part way up the tree.
Scoot A two-runner sled, without tongue or shafts, used to haul logs or bolts from the woods.
Scratch coat. The first coat of plaster, which is scratched to form a bond for the second coat.
Screed. A small strip of wood, usually the thickness of the plaster coat, used as a guide for plastering.
Screw Gun A tool used to install sheetrock, also known as drywall. Screw guns look like a normal drill, although they have a “nose” as opposed to a chuck. The nose holds an interchangeable shank bit, commonly known as a tip.
Scribing Shaping one member to the surface which it touches; for example, to fit a board snugly to a surface which is not straight.
Scribing. Fitting woodwork to an irregular surface. In moldings, cutting the end of one piece to fit the molded face of the other at an interior angle to replace a miter joint.
Scribner Rule The diagram log rule, one of the oldest in existence, that assumes 1-inch boards and ¼-inch kerf, make a liberal allowance for slabs, and disregards taper. This is the official rule of the Canadian Forestry Branch, Department of Resources and Development, and also used in many part of the United States.
Sealed Bid Sale Sale in which interested parties submit written bids at the time and place specified.
Sealer. A finishing material, either clear or pigmented, that is usually applied directly over uncoated wood for the purpose of sealing the surface.
Seasoned Wood that has been dried to a certain moisture content to improve its serviceability. According to the grading standards of the Western Wood Products Association, seasoned softwood lumber is defined as having a moisture content of 19% (oven-dry basis) or less.
Seasoning The process of removing the moisture from green wood to improve its workability and stability.
Seasoning. Removing moisture from green wood in order to improve its serviceability.
Second Growth Trees that come up naturally after the first growth of timber has been cut or destroyed by fire. This is also known as young timber.
Secondary Logging Road A road designed for relatively little use. Typically, a dirt road, with no gravel, used only during dry weather.
Secondary Rafters Smaller sized timber rafters placed between principle rafters.
Secondary Transport Movement of wood from the landing or transfer point. This includes movement by truck, rail, or water.
Secondary Wood This is the material used in furniture that is not seen or on the sides or back of an object. These are the materials that make up the drawer sides, dust panels, backs and other hidden parts.
Section A land survey subdivision. This is usually one square mile (640 acres).
Seed Block Used to describe uncut blocks of trees that are left between and around small clear-cut blocks to provide seeds for natural regeneration.
Seed Tree A horizontal timber to which the tops of rafters are fastened. This is also called a ridge board or a roof tree.
Seedbed An area prepared to receive seeds, such as an area cleared of plants and duff, so that natural seed fall can establish a new forest.
Seedling A young tree grown from a seed, from the time of germination until it reaches sapling size. In nursery practices it is a young tree that has not been transplanted.
Seedling and Sapling Stands Where ten percent of the stand consists of growing-stock trees, and saplings and/or seedlings constitute more then half this stocking.
Select In softwood lumber, the highest appearance grades are Select grades, usually separated as “B and better”, “C”, and “D” select grades. In hardwood factory lumber, Selects is one specific grade, placing in quality below Firsts and Seconds, but higher than Common grades.
Select Grade High-quality lumber. This grade is recommended for all finishing uses where fine appearance is essential. Widely used for high-quality interior trim and cabinet work with natural, stain, or enamel finishes.
Selection Cutting Cutting only a portion of the trees in a stand; usually those marked or designated by a forester.
Selection System Uneven-aged silvicultural system in which single or small groups of trees are periodically selected to be removed from a large area so that the age and size classes of the reproduction are mixed.
Selection Thinning Removal of dominant trees that have exceeded the diameter limit prescribed; in favor of smaller trees with good growth form and condition. This will promote conversion to a selection forest.
Selective Cut A type of timber harvesting that removes only certain species above a certain size or value.
Selects In softwood, lumber which has been graded strictly for its appearance. In hardwood, lumber which is one grade below first and second.
Self Loader Logging truck with a loading device, generally a knuckleboom loader, mounted behind the cab.
Semigloss paint or enamel. A paint or enamel made with a slight insufficiency of nonvolatile vehicle so that its coating, when dry, has some luster but is not very glossy.
Semitransparent Stain A suspension of pigments in a drying oil designed to color and protects wood surfaces by penetration without forming a surface film and without hiding wood grain.
Separator Wood Material that has been separated from the whole tree during the chipping process and is unacceptable for pulp and paper manufacture. This is usually used as energy wood.
Set The teeth are offset on each side of the blade to allow clearance for the thickness of the blade.
Setback The area along a property’s edge where new construction is restricted or forbidden by local zoning laws.
Setting Area logged to an one yarder set-up.
Shackle A clevis or U-shaped metal fitting with a pin through the ends.
Shade Structure A structure built above decks, usually of posts and lattice, to provide a shaded area on the deck.
Shake A lumber defect that is a lengthwise separation of wood; along the growth rings.
Shake. A thick handsplit shingle, resawed to form two shakes; usually edge-grained.
Shakes Shakes are very similar to checks, but usually wider and longer. They generally work from the heart of the tree outward, at right angles rather than parallel to the growth rings.
Shaper A machine with an interchangeable rotary cutter head to cut profile shapes on the edge or face or material
Shaving A small wood particle of indefinite dimensions developed incidental to certain woodworking operations involving rotary cutter heads usually turning in the direction of the grain.
Shay Swivel A fitting used to attach the slack-pulling line to the main line on a skyline system.
Shear Hydraulically operated scissor-like device for crosscutting the stem of a tree. One type of tree shear uses a cutting blade, which closes parallel to the anvil.
Shearing Strength The capacity of an object or soil to resist shearing stresses.
Sheathing Lumber, Plywood, oriented strand board, or wafterboard used to close up side walls, floors or roofs prior to the installation of finished materials on the surface. The sheathing grades are also commonly used for crates, pallets, and certain industrial products.
Sheathing paper. See Paper, sheathing.
Sheathing. The structural covering, usually wood boards or plywood, used over studs or rafters of a structure. Structural building board is normally wed only as wall sheathing.
Sheave A grooved wheel or pulley.
Sheep’s Foot Roller A steel drum with short metal rods on the outside; sometimes shaped like a sheep’s foot. This is used for compacting soil.
Sheet metal work. All components of a house employing sheet metal, such as flashing, gutters, and downspouts.
Shellac Resin flakes dissolved in alcohol used as a finish for wood.
Shellac. A transparent coating made by dissolving lac, a resinous secretion of the lac bug (a scale insect that thrives in tropical countries, especially India), in alcohol.
Shelterwood Logging A method of harvesting timber so that selected trees remain scattered throughout the tract to provide seeds for regeneration and shelter for seedlings.
Shelterwood System Even-aged silvicultural system in which a new stand is established under the protection of a partial canopy of trees. The mature stand is generally removed in a series of two or more cuts, the last of which is when the new even-aged stand is well developed.
Shingles, siding. Various kinds of shingles, such as wood shingles or shakes and nonwood shingles, that are used over sheathing for exterior sidewall covering of a structure.
Shingles. Roof covering of asphalt. asbestos, wood, tile, slate, or other material cut to stock lengths, widths, and thicknesses.
Shiplap. See Lumber, shiplap.
Shipping Dry Having moisture content (over-dry basis) of 14 to 20 percent. Results in reduced shipping weight and less susceptibility to decay. This is used in the international lumber trade.
Short Rotation Energy Plantations Plantings established and managed under short-rotation intensive culture practices.
Short Ton U.S. weight measure equal to 2,000 pounds.
Shortwood Pulpwood less than 120 inches in length. Trees or stemwood portions of trees delivered in product lengths of less than 15 feet and normally considered only for pulpwood.
Shotgun A two-drum, live skyline yarding system used in uphill logging, in which the carriage moves down the skyline by gravity, is lowered to attach logs, and is then raised and pulled to the landing by the main line.
Shoulder The area of the void created when the waste around a tenon has been cut away.
Shovel A tool with a handle and a broad scoop or blade for digging and moving material, such as dirt or snow.
Show Any unit of operation in the woods associated with timber harvesting.
Shrinkage A decrease in wood dimensions due to loss of water in the wood cell walls. Shrinkage across the grain of wood occurs when the moisture content falls below 30 percent, the fiber saturation point. Below the fiber saturation point, shrinkage is proportional to moisture content, down to a moisture content of zero percent. Shrinkage is expressed as a percentage of the green wood dimensions.
Shutter. Usually lightweight louvered or flush wood or nonwood frames in the form of doors located at each side of a window. Some are made to close over the window for protection; others are fastened to the wall as a decorative device.
Shuttle Hauling Use of preloading trailers to reduce truck turn-around time.
Shy A term for an adjoining object being below the object it is next to. This means a little below the surface.
Side Men and equipment needed to yard and load any one logging unit of an operation.
Siding The finish covering of the outside wall of a fame building, whether made of horizontal weather boards, vertical boards with battens, shingles, or other material.
Siding, bevel (lap siding). Wedge-shaped boards used as horizontal siding in a lapped pattern. This siding varies in butt thickness from ½ to ¾ inch and in widths up to 12 inches. Normally used over some type of sheathing.
Siding, Dolly Varden. Beveled wood siding which is rabbeted on the bottom edge.
Siding, drop. Usually ¾ inch thick and 6 and 8 inches wide with tongued-and-grooved or shiplap edges. Often used as siding without sheathing in secondary buildings.
Siding. The finish covering of the outside wall of a frame building, whether made of horizontal weatherboards, vertical boards with battens, shingles, or other material.
Sill Timber Major horizontal timbers which lie on the foundation and form the lowest part of the frame.
Sill. The lowest member of the frame of a structure, resting on the foundation and supporting the floor joists or the uprights of the wall. The member forming the lower side of an opening, as a door sill. window sill. etc.
Silvicultural System The process of tending, harvesting, and replacing forest trees, which results in the production of forests with distinct compositions. Systems are classified according to the method of harvest cutting used for stand reproduction.
Silviculture The science and art of cultivation (such as with growing and tending) forest crops, based on the knowledge of silvics. More explicitly, the theory and practice on controlling the establishment, composition, constitution, and growth of forests.
Single Spread Refers to application of adhesive to only one adherent of a joint.
Single-Action Shear A mechanized cutting tool that uses one hydraulic cylinder to push the cutting blade through the tree while a fixed anvil provides support for the blade on the trees opposite side.
Single-Span Skyline Skyline without intermediate support spars.
Single-Stem An operation handling one tree at a time.
Site Built A structure constructed at the site where it is to remain.
Site Class Classification based on ecological factors and the potential production capacity of an area; a measure of the relative production capacity of a site.
Site Index The measure of forest productivity generally expressed as the height in feet of dominant and co-dominant tree species at a specific index age such as 25, 50, or 100 years. Sit indexes are normally grouped by site classes.
Site Preparation Removal or deadening of unwanted vegetation prior to planting trees; includes prescribed burning, use of herbicides, disking and other mechanical means of removing vegetative cover.
Site Utilization A term used when indicating the proportion of a useable forest site occupied by healthy, vigorous forest crop trees at any one point in time.
Six-By-Six A motor truck with six powered wheels, two in front and four in back.
Skid Pole Logs or poles, commonly used in pairs, on which logs are rolled.
Skid Trail Skidder path through the woods.
Skidding Chain The length of chain fastened around the end of a log.
Skidding Pan A plate of heavy steel, round in front, placed under the front end of logs being skidded to prevent them from digging into the ground.
Skidding Tong The tong used in skidding to grasp a log.
Skirt A decorative board placed around the support structure of a deck to hide the structure below and give the deck a finished appearance. Skirts often are attached to the joists.
Skyline Cableway stretched tautly between two spar trees and used as a track for a skyline carriage.
Skyline Carriage A wheeled device that rides back and forth on the skyline for yarding or loading.
Skyline Crane A yarding system capable of moving logs laterally to a skyline as well as transporting logs either up or down a skyline to a landing.
Skyline Crane Carriage Skyline carriage that incorporates provisions for pulling slack in the skidding line.
Skyline Road An area bounded by the length and lateral yarding width of any given skyline setting.
Skyline Slope The slant or inclination of the skyline chord, generally expressed as a percent.
Slackline System A live skyline system employing a carriage, main line, and haul-back line. Both main and haul-back lines attach directly to the carriage. The skyline is lowered by a slackening of the line to permit the chokers to be attached to the carriage. Lateral movement is provided by side blocking. For drum standing skyline yarding systems in which either the slack pulling line pulls the main line through the carriage or a carriage that contains a skidding line is used. The haul-back line returns the carriage and holds it in place during lateral yarding.
Slack-Pulling Line A line used to pull the main line through a logging carriage.
Slash Woody material or debris left on the ground after an area is logged. This is also known as brush.
Slasher A machine that bucks Longwood into Shortwood at the landing. This is also known as a bucker.
Sleeper. Usually, a wood member embedded in concrete, as in a floor, that serves to support and to fasten subfloor or flooring.
Slick A wide bladed and long handled chisel pushed by hand to create flat surfaces.
Sliding Miter Saw A compound miter saw with horizontal sliding arms for the cutter head, allowing much wider cuts.
Sling A loop of wire rope used in loading logs too large to be handled by tongs.
Slip Relative movement in the direction of travel at the mutual contact surface of the traction or transport device and the surface that supports it.
Slip Grab A pear-shaped link, attached by a swivel to a chain. The chain runs freely through this chain when the large end is down but catches and holds when the small end is down.
Slip Hook A rounded hook that permits a chain to run freely through it.
Sloop A two-runner sled to haul logs or bolts out of the woods. Similar to a scoot except that the sloop is equipped with a tongue.
Small Trees Live trees 1.0 to 5.0 inches to D.B.H.
Smallwood A general term describing small-diameter material (such as what might be removed by a pre-commercial thinning) that is typically unsuitable for commercial roundwood products.
Snag A standing dead tree from which the leaves and most of the branches have fallen.
Snipe The tendency to gouge the trailing end of material when running it through a joiner.
Snubbing Line A line used for lowering a load.
Soffit. Usually the underside of an overhanging cornice.
Soft Maple Creamy white and straight grained
Soft Rot Rot occurring in the outer wood layers under very wet conditions.
Softwoods Lumber often from a conifer, such as pine or cedar. The name softwood does not refer to the density of the wood. There are some hardwoods which are softer then some softwood.
Soil Adhesion The sticking of soil to foreign materials such as soil implements, tracks, or wheels.
Soil Compaction Increased soil density resulting from the packing effect of machines moving over the soil. Compaction disturbs the soil structure and can cause decreased tree growth, increased water runoff, and soil erosion.
Soil cover (ground cover). A light covering of plastic film, roll roofing, or similar material used over the soil in crawl spaces of buildings to minimize moisture permeation of the area.
Soil Failure Alteration or destruction of the soil structure by mechanical forces such as in shearing, compression, or tearing.
Soil stack. A general term for the vertical main of a system of soil, waste, or vent piping.
Sole or sole plate. See Plate.
Solid bridging. A solid member placed between adjacent floor joists near the center of the span to prevent joists from twisting.
Solid Piling (Bulk Piling) The close stacking of lumber or other products, without separation of layers with stickers, as in open piling.
Sorting The separation of forest products. This usually occurs at the landing.
Sound A term referring to a board which has no or very few defects which will effect its strength.
Sound Wood Wood that is free from defect.
South American Lacewood Pink to reddish-brown color
Southeastern States Virginia, North Carolina, South Carolina, Georgia, and Florida.
Southern States Alabama, Mississippi, Texas, Louisiana, Arkansas, and Tennessee.
Southern Yellow Pine A species group composed of primarily of Loblolly, Longleaf, Shortleaf, and Slash Pines. Various subspecies are also included in this group. This group refers to the Southeastern United States, from Texas to Virginia.
Spacing Control The act of creating, within the limits of the existing stand, a uniform distribution of trees that provides optimum growing space for each tree by eliminating overcrowding. As a result, tree diameter growth is increased and the time required for the forest to reach harvestable size is decreased.
Spade Bit These are an inexpensive bit, suitable for general use, they get their name from their shape.
Span The width of a building or overall length of a truss.
Span. The distance between structural supports such as walls, columns, piers, beams, girders, and trusses.
Spanish Cedar Pale pinkish-brown heartwood
Spar Tree A tree or mast on which rigging is hung for one of the many cable hauling systems.
Species A category of biological classification; a class of individuals having common attributes and designated by a common name. “Species” is always properly used with the “s” when referring to trees or other biological classifications.
Specific Adhesion Adhesion between surfaces that are held together by valence forces of the same type as those that give rise to cohesion.
Specific Gravity The ratio of the weight of wood to an equal volume of water. The higher the specific gravity, the heavier the wood.
Speck A defect that’s caused by a fungus living in a tree, which appears as small white pits of spots.
Speed Square The rafter angle square is a triangular-shaped measuring tool used to draw straight lines on lumber to be cut, or to lay out angles for roofs, stairways, decks and other general construction. The tool is marked with degree gradations for fast layout and cutting of lumber without performing complex trigonometry calculations.
Splash block. A small masonry block laid with the top close to the ground surface to receive roof drainage from downspouts and to carry it away from the building.
Splating An attractive dark brown or black stain in some woods caused by decay. A change in the texture, strength and color of wood caused by colonies of fungus growing within the dead wood.
Splicer One who joins two pieces of cable together by intertwining the wire strands.
Spline A thin strip of wood fitting between two grooves to make a joint.
Split A separation of wood fibers that extends completely through a piece of lumber, usually at the ends.
Spokeshave Used to shape curved surfaces, consists of a blade fastened between two handles, blades come in straight concave and convex curves.
Spot To place a truck or trailer in position for loading.
Spray Gun A cloud of mist of fine liquid particles, as of water from breaking waves.
Spread The quantity of adhesive per unit joint area applied to an adherent.
Spring Steel Alloy A type of hardened steel that has both hardness and yield strength.
Spruce-Pine-Fir (SPF) Canadian woods of similar characteristics that have been grouped for production and marketing. The SPF species have moderate strength, are worked easily to take paint readily and hold nails well. They are white to pale yellow in color. The largest volume comes from eastern Canada, where the principal species in the group are: Black Spruce, Red Spruce, Jack Pine, and Balsam Fir. The principal species of the group originating in Western Canada are Alpine Fir, Engelmann Spruce, Lodgepole Pine, and White Spruce. Some lumber production in the New England State also is marketed as Spruce-Pine-Fir (south).
Spud Tool with a narrow-shaped, curved blade used in removing bark by hand. This is also called a barking iron.
Spur Road A road that supports a low level of traffic, such as a level that would serve one or two settings. Little or no engineering design work is needed to build it.
Square An instrument used to lay out or test right angles, with two arms at 90 degrees to each other; the longer and wider arm is the blade, the shorter narrower arm is the tongue.
Square. A unit of measure—100 square feet—usually applied to roofing material. Sidewall coverings are sometimes packed to cover 100 square feet and are sold on that basis.
Squeeze Out Bead of adhesive squeezed out of a joint when pressure is applied.
Stacked Dado Head style of dado cutter has two outside saw blades, using a combination of chipper blades and shims between them the width of the dado is set.
Stacker A mobile machine for unloading and stacking or decking logs using the forklift principle and curved top clamps. A heavy-left machine similar to a front-end loader, with forks and clamps capable of handling and loading logs.
Staggered Setting Cleat-cut settings separated by uncut timber.
Stain A discoloration in wood caused by a chemicals, fungus, or minerals. A dye or pigment used to discolor wood.
Stain, shingle. A form of oil paint, very thin in consistency, intended for coloring wood with rough surfaces, such as shingles, without forming a coating of significant thickness or gloss.
Stair carriage. Supporting member for stair treads. Usually a 2-inch plank notched to receive the treads; sometimes called a “rough horse.”
Stair landing. See Landing.
Stair rise. See Rise.
Stand In Silviculture and management, a tree community that possessed sufficient uniformity in composition, constitution, age, spatial arrangement, or condition to be distinguishable from adjacent communities. This tree community forms a silvicultural or management entity; for example, a sub-compartment. Both natural and artificial crops are included, and there is no connotation of a particular age. In Mensuration, the amount of timber and/or fuelwood standing on an area, generally expressed as volume per unit area; for example, board feet per acre or cubic meters per hectare. In the United States, growth of trees on minimum of one acre of forest land that is at least 16.7 percent stocked by forest trees of any size.
Stand Condition The general health of a stand of trees reflected by its development relative to the site potential. A good stand condition refers to a fully stocked stand that is producing fiber at a high rate based on specific site conditions such as moisture, soil quality, and other biological variables.
Stand Density The number of merchantable trees per acre. A quantitative measure of tree stocking frequently expressed in terms of number of trees, basal area, or volume per unit area.
Stand Improvement Measures such as thinning, release cutting, girdling, weeding, or poisoning of unwanted trees to improve growing conditions.
Stand Table A table showing the number of trees by species and diameter classes, generally per unit area of a stand. Such data may be presented in the form of a frequency distribution of diameter classes.
Standard A tooth form that has evenly spaced teeth, deep gullets, and a zero-degree rake angle.
Standing Line A fixed cable that does not move during logging operations; for example, a skyline anchored at both ends.
STC. (Sound Transmission Class). A measure of sound stopping of ordinary noise.
Stem The main body of a tree from which branches grow. Used loosely to refer to trees. For example, stems per unit area.
Stemwood Wood from the main part of a tree, not from the branches, stump, or root.
Stick A piece of short pulpwood.
Sticker A ¾” to 1” wood strip that is inserted between stacks of green wood and spaced between 16” to 24” to allow air to flow through the stack to ensure proper drying.
Sticker Stain Sometimes called shadow, it’s a stain that forms under the stickers in a stack of drying wood.
Stiff Leg A loader with a boom that does not swing.
Stile. An upright framing member in a panel door.
Stock A handle of a peavey or cant hook.
Stocking The degree of utilization of land by trees. Measured in terms of basal area and/or the number of trees in a stand compared to the basal area and/or number of trees required to fully utilize the growth potential of the land. A stocking percent of 100 indicates full utilization of the site and is equivalent to 80 square feet of basal area per acre in trees five inches in D.B.H. or larger. A stocking percent of 100 in a stand of trees less than five inches in D.B.H would indicate that the percent number of trees is sufficient to produce 80 square feet of basal area per acre when the trees reach five inches D.B.H. A stocking percent over 100 is fully utilizing the site.
Stool. A flat molding fitted over the window sill between jambs and contacting the bottom rail of the lower sash.
Stop The decorative end of a chamfer.
Storage Life The period of time during which a packaged adhesive can be stored under specific temperature conditions and remain suitable for use.
Storied A term applied to the axial cells and rays in wood when these are arranged in horizontal series on tangential surfaces.
Storm sash or storm window. An extra window usually placed outside of an existing one, as additional protection against cold weather.
Story Stick A “story stick” or “story pole” is a scrap strip of wood used to record dimensions for a project on site, then the dimensions are used in the ship to build the project. This method reduces the chance or error due to misreading numbers etc.
Story. That part of a building between any floor and the floor or roof next above.
Strap A short cable with a loop at each end.
Straw Drum A small drum on a yarder that handles the straw line.
Straw Line A light-weight line used to change main skidding lines and tackle in cable yarding systems.
Strength The ability of a member to sustain stress without failure.
Strength Ratio The hypothetical ratio of the strength of a structural member to that which it has if it contained no strength-reducing characteristics.
Stress Skin Construction A construction in which panels are separated from one another by a central partition of spaced strips with the whole assembly bonded so that it acts as a unit when loaded.
Stress Wave Timing A method of measuring the apparent stiffness of a material by measuring the speed of an induced compression stress as it propagates through the material.
String, stringer. A timber or other support for cross members in floors or ceilings. In stairs, the support on which the stair treads rest; also stringboard.
Stringer A timber or other support for cross members in floors or ceilings.
Strip flooring. Wood flooring consisting of narrow, matched strips.
Stripe A stripe of ribbon pattern that occurs when woods with interlocked grain, which slopes in alternate directions, are quarter-sawn.
Structural Composite Lumber (SCL) Wood elements glued together to form products that are similar in size to solid sawn lumber.
Structural Integrity A structure uncompromised ability to safely resist the required loads.
Structural Timbers Pieces of wood of relatively large size, the strength or stiffness of which is the controlling element in their selection and use.
Strut A short timber placed in a structure either diagonally or vertically; designed to act in compression along the direction of its lengths.
Stucco. Most commonly refers to an outside plaster made with Portland cement as its base.
Stud A framing member, usually cut to a precise length at the mill and designed to be used in framing building walls with little or no trimming before it is set in place. Studs are most often 2x4s, but 2x3s, 2x6s, and other sizes are also included in the stub category; studs may be made of wood, steel, or composite material.
Stud. One of a series of slender wood or metal vertical structural members placed as supporting elements in walls and partitions. (Plural: studs or studding.)
Stump Jumper A heavy plate underneath a skidder that protects the back housing from contact with high stumps.
Stump Pull Slivers of wood remaining attached to the stump after a tree is felled; the slivers are considered as having been pulled from the butt of the log.
Stumpage The value of timber as it stand uncut in the woods.
Stumpwood Wood cut into short lengths and piled near the stumps.
Stumpwood Chips Chips manufactured from Stumpwood.
Style or Stile A vertical member of a door’s framework attached to the horizontal rails.
Subfloor. Boards or plywood laid on joists over which a finish floor is to be laid.
Substrate A material upon the surface of which an adhesive containing substance is spread for any purpose, such as bonding or coating.
Substructure The deck construction that is located below, and supports the deck boards and railing system. Components include joists and hangers, ledgers, rim joists, beams, posts, anchors, and footers.
Sulky Logging arch equipment with wheels instead of crawler tracks and towed behind a skidding machine.
Summer Beam A major horizontal timber which spans the girts or plates.
Suppressed One of the four major crown classes, specifically trees with crowns entirely below the general level of the crown cover receiving no direct light either from above or from the sides. This is also known as overtopped.
Surface Inactivation In adhesive bonding to wood, physical and chemical modification of the wood surface that result in reduced ability of an adhesive to properly wet, flow, penetrate, and cute.
Surface Tension The force per unit length acting in the surface of a liquid that opposes the increase in area of the liquid.
Surfaced Checks A drying defect that occurs when the surface dries too quickly in relation to the core.
Surfaced Lumber A piece of wood that has been planed smooth on one or more surfaces.
Surfacing The way a piece of lumber has been prepared at the lumber mill.
Suspended ceiling. A ceiling system supported by hanging it from the overhead structural framing.
Sustainable Forest Initiative (SFI) This is a program that was established in 1994 and currently certifies over 152 million acres in the United States and Canada. It is based on the premise that responsible forest practices and sound business decisions can co-exist. Independent certification bodies evaluate planning, procedures, and processes in the forest and in wood processing operations.
Sustained Yield Timber yield that a forest can produce continuously at a given intensity of management. Sustained yield management therefore implies continuous production planned to achieve a balance between growth (increment) and harvest at the earliest practical time.
Swamp An area saturated with water throughout much of the year, but with the surface of the soil usually not deeply submerged. This is usually characterized by tree or shrub vegetation.
Swamp Buggy A Skidder equipped with high floatation tires.
Sweep A gradual bend in a standing tree or in a log, pole, or piling.
Swell-Butted Trees greatly enlarged at the base.
Swivel Universal joint used in rigging to prevent lines from twisting.
Symmetrical Construction Panels in which the plies on one side of a center ply or core are essentially equal in thickness, grain direction, properties, and arrangements to those on the other side of the core.


Table Saw A circular saw mounted under a table with height and angle adjustments for the blade.
Tack The property of an adhesive that enables it to form a bond of measurable strength immediately after adhesive and adherent are brought into contact under low pressure.
Tack Cloth or Tack Rag A cloth permeated with a sticky substance to wipe up the dust from sanding when finishing a project.
Tack Time The amount of time it takes for an adhesive to set-up before it can form a bond.
Tackle The combination of blocks and ropes used in cable logging.
Tagline Extra length of line at the end of a main line. Used as an extension for carrying additional choker hooks or to dampen the swing of a bucket or grapple on a boom-type loader.
Tail The end portion of a birds-mouth joint which extends beyond the plate when there is a roof overhang.
Tail beam. A relatively short beam or joist supported in a wall on one end and by a header at the other.
Tail Block A block fixed to a stump at the outer edge of a setting, in ground-lead and high-lead cable logging, or to the tail spar, in skyline cable logging, through which the haul-back line is reeved for returning the main line and the butt rigging to the loading point.
Tail Tree A tree to which the far end of the skyline is attached. This is also known as a tail spar.
Tailhold In cable logging, the anchorage at the outer end of the skyline away from the landing. This is also known as a tailholt.
Tandems The second axle and set of wheels on the rear of a truck. Live indicates that they are powered; dead that they are not.
Tangential Coincident with a tangent at the circumference of a tree or log, or parallel to such a tangent.
Taper A piece of wood that has been cut so that it is wider on one edge compared to the other.
Taper Cut The new wood in a tree that lies between the bark and the heartwood. Sapwood is usually lighter in color and becomes heartwood as the tree ages.
Tar Heel A name given to loggers from any Southeastern state.
Target Forest A type of forest, in terms of species mixture, size, stocking, and harvest age, considered best for a particular site in order to economically produce fiber in the qualities desires on a perpetual basis.
Teak Golden-brown color to darker chocolate-brown
Tear-Out The tendency for a blade to splinter the last part of a piece of wood during crosscutting.
Technical Life Length The time from which the machine goes into operation until it is no longer used in any operation. Normally, the unit for technical life length is productive time, expressed in hours.
Tempered Hardboard Dense fiberboard that has been specially treated to increase its durability, strength, density, and moisture resistance.
Template A pattern. Often a template is made of hardboard and used with a pilot bit to route a shape in a board.
Template Guide A jig mounted to the bottom of a router that is used to keep the router on the profile of a template when routing with a non-pilot beating bit.
Tenon The projecting end of a timber that is inserted into a mortise.
Tension In an adhesively bonded joint, a uni-axial force tending to cause extension of the assembly, or the counteracting force within the assembly the resists extension.
Tension Wood Reaction wood that forms on the upper side of a leaning hardwood tree.
Termite shield. A shield, usually of noncorrodible metal, placed in or on a foundation wall or other mass of masonry or around pipes to prevent passage of termites.
Termites. Insects that superficially resemble ants in size, general appearance, and habit of living in colonies; hence, they are frequently called “white ants.” Subterranean termites establish themselves in buildings not by being carried in with lumber, but by entering from ground nests after the building has been constructed. If unmolested, they eat out the woodwork, leaving a shell of sound wood to conceal their activities, and damage may proceed so far as to cause collapse of parts of a structure before discovery. There are about 56 species of termites known in the United States; but the two major ones, classified by the manner in which they attack wood, are ground inhabiting or subterranean termites (the most common) and dry wood termites, which are found almost exclusively along the extreme southern border and the Gulf of Mexico in the United States.
Terneplate. Sheet iron or steel coated with an alloy of lead and tin.
Tether Line A line used to restrain a balloon in flight; such as the line from a logging balloon to the butt rigging.
Texture The size of the cells in wood, described as ranging from coarse to fine; often confused with grain.
Thermoplastic A material that will repeatedly soften when heated and harden when cooled.
Thermoset A cross-linked polymeric material.
Thermosetting Having the property of undergoing a chemical reaction by the action of heat, catalyst, ultraviolet light, and hardener, leading to a relatively infusible state.
Thickness Planer A power-fed rotary planer that trims the surface of a board to a certain thickness.
Thinning Cuttings made in immature stands in order to stimulate the growth of trees that remain and to increase the total yield of useful material from the stand.
Thousand Board Feet A unit of measurement equal to 1,000 feet of wood having a thickness of one inch.
Threshold. A strip of wood or metal with beveled edges used over the finish floor and the sill of exterior doors.
Through Dovetail Joint A method of joining wood where the interlocking pins and tails of the dovetail joint go through the side of its mating piece.
Thumbnail A small rough sketch of the deck and its site.
Tig Welder An arc welding process that sues a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas, usually an inert gas such as argon, and a filler metal is normally used, though some welds, known as autogenously welds, do not require it.
Tightlining A method of high-lead cable yarding in which the haul-back line supports the butt rigging and makes it possible to lift the butt rigging and its load over obstacles.
Tilt Blade A blade that can be tilted in respect to a vertical position.
Tilt Cab A cab on a machine that is hinged on one side and can be tilted back and lowered for transport.
Timber A general term applied to a forest and its products. Sawed lumber more then 4×4 inches in breadth and thickness.
Timber Appraisal An economic appraisal of the monetary value of a timber stand.
Timber Frame A load-carrying structure of timbers ranging in size from 4×4 and up.
Timber Products Output Timber products cut from roundwood and byproducts of wood-manufacturing plants. Roundwood products include logs, bolts, and other round sections cut from gowning stock trees, cull trees, salvable dead trees, tree on non-forest land, noncommercial species, sapling-size trees, and limbwood. Byproducts from primary manufacturing plants include slabs, edging, trimming, mis-cuts, sawdust, shavings, veneer cores and clippings, and screenings of pulpmills that are used as pulp chips or other products.
Timber Removals from Growing Stock The volume of sound wood in live sawtimber, forest products (including roundwood products and logging residues), and other removals. Roundwood products are logs, bolts, or other round sections cut from trees. Logging residue are the unused portions of cut trees plus unused trees killed by logging. Other removals include growing stock trees removed by cultural operations such as timber stand improvement work and by land clearing and changes in land use.
Timber Removals from Sawtimber The net board-foot volume of live sawtimber trees removed annually for forest products, including roundwood products and logging residues, and other removals, such as growing stock trees removed by cultural operations, timber stand improvement work, land clearing, and changes in land use.
Timber Stand Improvement The intermediate thinning of a forest stand, prior to it reaching mature rotation age, generally for the purpose of improving growing conditions or controlling stand composition.
Timber Standing Timber still on the stump.
Timber Volume Volume of Growing Stock – The volume of sound wood in the bole of sawtimber and poletimber from a stump to a 4-inch minimum top diameter outside bark or to the point where the central stem breaks into limbs. Volume of Sawtimber – The net volume of the saw log portion of live sawtimber in board feet.
Tip The point of the saw blade tooth that digs in and cuts the work piece.
TLL Technical Life Length.
Toe Kick An indentation designed into the bottom of a cabinet to provide room to allow the user to stand closer to the countertop.
Toenailing. To drive a nail at a slant with the initial surface in order to permit it to penetrate into a second member.]
Toggle Clamp Clamps which can be attached to a base or table to hold work.
Tongs A pair of curved arms that pivot like scissors so that a pull on the ring connecting the shorter segments will cause the points on the long segments to bite into the logs. The tongs are activated by the pull on the loading line. Loading tongs without sharp points powered by air or hydraulic cylinders that close on a log.
Tongue and Groove A joinery method where one board is cut with a protruding “groove” and an identical piece is cut with a matching groove along its edge.
Tongued and grooved. See Dressed and matched.
Tooth Back The read side of a saw blade tooth facing away from the direction of the cut.
Tooth Back Clearance Angle The angle that measures the amount of space, or clearance between the tooth back and the work piece.
Tooth Face The front side of a saw blade tooth facing toward the direction of the cut.
Tooth Form The shape and geometry of a tooth.
Tooth Pitch The distance between one tooth tip and the next.
Tooth Rake Angle The angle formed by the tooth face and a line perpendicular to the back of the blade.
Tooth Set The side to side bending of teeth. Tooth Set if used to widen the cut and prevent pinching of the blade.
Top To cut off the unmerchantable top of a tree.
Top Lopping To cut limbs from downed tree tops so that no limbs are more than a specified length along the tree stem.
Top Plate Attached to the posts and the top rail to support the top rail and balusters. It is also known as the top cap.
Top Rail The horizontal member installed on the edge; attached to the top of the balusters as well as the posts.
Topo A topographic map. This shows the elevation contours of the ground.
Torpedo Level A short level used in deck building to set posts plumb. It is sometimes referred to as a canoe level.
Torque The amount of force that is needed to turn an object such as a screw or bolt.
Torque Converter A centrifugal pump, driven by an engine, that rotates in a case filled with oil.
Torx Head A screw head requiring a driver in the shape of a star.
Total Tree A tree with a crown, main stem, and taproot. This does not include the lateral roots.
Toughness A quality of wood that permits the material to absorb a relatively large amount of energy, to withstand repeated shocks, and to undergo considerable deformation before breaking.
Tower A steel mast used instead of a spar tree at the landing for cable yarding.
Tracheary Elements The principal water-conducting elements of the xylem, mostly vessel members and tracheids.
Tracheids An imperforate wood cell with bordered pits.
Tractor A powered vehicle for off-the-road hauling. May be mounted on crawler tracks of wheels. A short wheelbase truck used to haul trailers.
Transferring Lifting an entire load of logs from one mode of transportation and placing the logs on another carrier.
Transit A transit level is a means of measuring, or surveying as it is also known, the location, elevation, degree of inclination of any object such as buildings, trees, fences, relative to the placement of the transit.
Tread The walking surface of each step in a stairway.
Tread. The horizontal board in a stairway on which the foot is placed.
Treated Wood products infused or coated with any variety of stains or chemicals designed to retard decay, deterioration, fire, or insect damage due to weather.
Tree A woody plant that usually grows to at least 20 feet in height at maturity and commonly has a single trunk with no branches within three feet of the ground.
Tree Farm A parcel of land on which trees are planted, cultured, managed, and harvested as a crop. Also, privately owned, managed forest area that has been certified as a tree farm by the American Forest Institute.
Tree Farming The application of silvicultural practices for the perpetual use of commercial timber crops. Includes all activities from stand establishment through delivery of commercial timber (logs) to a log yard at the initial commercial product processing facility.
Tree Length The entire tree, excluding the Unmerchantable top and limbs.
Tree Shoe A device in the shape of a segment of a circle used to support the skyline from a spar tree.
Tree-Length Logging Felling and transporting the trimmed bole in one piece, whenever possible, for crosscutting at a landing or mill.
Trellis A framework of thin lumber designed to support climbing plants.
Trim The finish materials in a building, such as moldings, applied around openings or at the floor and ceiling of rooms.
Trim Allowance Extra length allowed when bucking logs or estimating volume to account for less from end injuries or uneven cuts.
Trim. The finish materials in a building, such as moldings applied around openings (window trim, door trim) or at the floor and ceiling of rooms (baseboard, cornice, and other moldings)
Trimmer. A beam or joist to which a header is nailed in
Triple Drum A three-drum yarder.
Tri-Square Is a woodworking or metal working tool used for marking and measuring a piece of wood. The square refers to the tool’s primary use of measuring the accuracy of a right angle; to try a surface is to check its straightness or correspondence to an adjoining surface.
Trolley A traveling block used in a skyline.
Trunnel Also known as a tree-nail, a turned and tapered hardwood dowel used for securing timber joints.
Truss An assembly of members, such as beams, bars, and rods combined to form a rigid framework. All members are interconnected to form triangles.
Truss. A frame or jointed structure designed to act as a beam of long span, while each member is usually subjected to longitudinal stress only, either tension or compression.
Try Square A square with a steel tongue in a wooden handle.
TSI Timber Stand Improvement.
T-Slot A slot milled in the shape of an upside down “T” to hold special bolts for clamps or jigs.
Tulipwood Heartwood is a beautiful pink-yellow with stripes varying in shades of salmon pink to rose red
Tungsten Carbide A very common material on any sort of cutting tool. Saw blades, drill bits, and router bits are made of carbide.
Turbocharger An air pump designed to put more air into engine cylinders; pump is driven by the exhaust heat.
Turn Logs yarded in any one top. Load of logs brought in by skidding unit during a single trip, landing to stump and return, made by a tractor or other skidding device.
Turnaround Time The time it takes for a truck or tractor to be loaded and unloaded.
Turnout An area of sufficient size, adjacent to a single lane road, that serves as a temporary parking place for vehicles so that oncoming vehicles may pass.
Turpentine. A volatile oil used as a thinner in paints and as a solvent in varnishes. Chemically, it is a mixture of terpenes.
Tusk Joint Also called a tuck or through tenon; a mortise and tenon joint in which the tenon goes all the way through the corresponding mortise.
Twist Warping in lumber where the ends twist in opposite directions.
Twitch “L” skid logs or tree lengths on the without an antifriction device.
Two-Storied Stand A forest stand in which two height classes of considerable difference occur: the over-story and understory. Does not apply to a forest in the process of reproduction, in which the appearance of two stories is due to a seed tree or shelter-wood cut before the final cut.
Tyloses A waterproof foam-like substance that forms in the pores of certain species of wood. The Tyloses help to make the wood less permeable to liquids. It is common in White Oak and makes the wood ideal for wine barrels.


Underbrush The brush under a stand of timber.
Undercoat. A coating applied prior to the finishing or top coats of a paint job. It may be the first of two or the second of three coats. In some usage of the word it may, become synonymous with priming coat.
Undercut A wedge-shaped notch cut in the base of a tree to govern the direction of its fall. This is also known as a box or a notch.
Underlayment A layer of plywood or other manufactured board used as a base material under finished flooring. Underlayment is often used as a substrate to increase the strength and/or smoothness of the flooring.
Underlayment. A material placed under finish coverings, such as flooring, or shingles, to provide a smooth, even surface for applying the finish.
Uneven-Aged Management A Silvicultural system in which individual trees originate at different times and result in a forest with trees of all ages and sizes. Harvest cuts are on an individual-tree selection basis.
Unloaded Deflection The vertical distance between the chord and the unloaded skyline, measured at mid-span.
Unmerchantable Wood Material that is unsuitable for conversion to industrial wood products due to size, form, or quality. May include rough, rotten, and dead trees; the tops, limbs, and cull sections fro, harvested trees; or small and noncommercial trees.
Upper Stem Portion Saw timber tree bole extending from above the merchantable top to as minimum four-inch top diameter outside bark or to the point where the central stems break into limbs.
Used for flooring stripes, interior and exterior joinery, and general construction work.
Utility Knife A cutting tool used in various trades and crafts for a variety of purposes. Designed to be lightweight, easy to carry and use.


V Joint Tongue and groove boards with their top corners beveled so when the two boards come together a “V” is formed.
Valley. The internal angle formed by the junction of two sloping sides of a roof.
VanDer Waal Forces Physical forces of attraction between molecules, which include permanent dipole, induced dipole, hydrogen bond, and Long dispersion forces.
Vapor barrier. Material used to retard the movement of water vapor into walls and prevent condensation in them. Usually considered as having a perm value of less than 1.0. Applied separately over the warm side of exposed walls or as a part of batt or blanket insulation.
Vapor Retarder A material with a high resistance to vapor movement, such as foil, plastic film, or specially coated paper, that is used in combination with insulation to control condensation.
Variable Costs Operation costs that result from running a machine, calculated on an hourly basis; includes cost of labor and items such as fuel, oil, wire rope, and replacement parts. Also known as operating costs.
Variable Positive A tooth form that has variable tooth spacing, standard tooth forms, varying gullet depth, and a zero-degree rake angle.
Varnish A liquid preparation that dries to a hard lustrous coating.
Varnish. A thickened preparation of drying oil or drying oil and resin suitable for spreading on surfaces to form continuous, transparent coatings, or for mixing with pigments to make enamels.
Vehicle.The liquid portion of a finishing material; it consists of the binder (nonvolatile) and volatile thinners.
Veneer A thin sheet of wood cut from a log; wood peeled, sawn or sliced into sheets of a given constant thickness and combined with glue to produce plywood or laminated-veneer lumber. Veneers laid up with the grain direction of adjoining sheets at the right angles produce plywood of great stiffness and strength; while those that lay up with grains running parallel produce flexible plywood most often used in furniture and cabinetry.
Veneer.Thin sheets of wood made by rotary cutting or slicing of a log.
Veneer-Core Plywood Plywood made from three or more pieces of veneer glued up in alternating-grain patterns.
Vent.A pipe or duct which allows flow of air as an inlet or outlet.
Vermiculite.A mineral closely related to mica, with the faculty of expanding on heating to form lightweight material with insulation quality. Used as bulk insulation and also as aggregate in insulating and acoustical plaster and in insulating concretefloors.
Very durable Used for heavy outdoor construction, bridge building, dock work, flooring, tool handles, furniture, and billiard tables.
Vessel An axial series of cells that have coalesced to form an articulated tube-like structure of indeterminate length. A union of wood cells which have open ends and are set one above the other, forming continuous tubes. The openings of the vessels on the surface of a piece of wood are usually referred to as pores.
Vessel Elements Wood cells in hardwoods of comparatively large diameter that have open ends and are set one above the other to form continuous tubes called vessels.
Virgin Timber Timber from an original forest that has not been previously disturbed or influenced by human activity.
Viscoelasticity The ability of a material to simultaneously exhibit viscous and elastic responses to deformation.
Viscosity A measurement of the thickness of a liquid.
Void The volume in the wood structure that is not occupied by wood tissue.
Volatile thinner.A liquid that evaporates readily and is used to thin or reduce the consistency of finishes without altering the relative volumes of pigment and nonvolatile vehicles.


Wall Decking Lumber covering the walls; usually 1” tongue-and-groove.
Wane Bark or lack of wood from any cause on edge or corner of a piece except for eased edges.
Wane. Bark, or lack of wood from any cause, on edge or corner of a piece of wood.
Warp A defect in lumber characterized by bending in one or more directions; any deviation of the face or edge of a board from flatness, or any edge that is not at right angles to the adjacent face or edge; the most common forms of warp are bow, crook, cup, and twist.
Wash Coat Typically used as the first coat of a finish. The wash coat is used to change the appearance or porosity of a surface.
Water Level A hose or tube filled with water, used in deck construction to transfer elevations from one post to another. The surface of the water at both ends of the hose must come to rest at the same height, allowing transfer of elevations.
Water Repellent A liquid that penetrates wood that materially retards changes in moisture content and dimensions of the dried wood without adversely altering its desirable properties.
Water Repellent Preservative A water repellent that contains a preservative that, after applications to wood and drying, accomplishes the dual purpose of imparting resistance to attack by fungi or insects and also retards changes in moisture content.
Water Table The upper limit of a saturated zone in the soil.
Water-repellent preservative.A liquid designed to penetrate into wood and impart water repellency and a moderate preservative protection. It is used for millwork, such as sash and frames, and is usually applied by dipping.
Wavy A tooth set that has groups of teeth set of one side then the other.
Weathering The mechanical or chemical disintegration and discoloration of the surface of wood caused by exposure to light, the action of dust and sand carried by winds, and the alternate shrinking and swelling of the surface fibers with the continual variation in moisture content brought by changes in the weather.
Weatherstrip. Narrower or jamb-width sections of thin metal or other material to prevent infiltration of air and moisture around windows and doors. Compression weather stripping prevents air infiltration, provides tension, and acts as a counter balance.
Wenge Clearly defined heartwood is dark brown with close, fine black streaks
Wet Strength The strength of an adhesive joint determined immediately after removal from water in which it has been immersed under specific conditions of time, temperature, and pressure.
Wet-Bulb Temperature The temperature indicated by the wet-bulb thermometer of a Psychrometer.
Wetland The transitional area between dry land and aquatic areas having a high water table of shallow water. Land with one of the following three attributes: (1) periodically supports hydrophytes, (2) substrate is predominately un-drained hydric soil, (3) substrate is non-soil and saturated or covered with water during part of the growing season each year.
Wettability A condition of a surface that determines how fast a liquid will wet and spread on the surface or if it will be repelled and not spread on the surface.
White Oak Varies from pale yellow-brown with a pinkish tint Straight grain
White Wood Wood products intended for treating, but not yet treated; a designation applied to a number of species such as White Fir.
Whole Tree All components of a tree, except the stump. This is also known as a full tree.
Width In band sawing, the distance from the top of the tooth to the back of the blade.
Winch A steel spool connected to a power source. Used for reeling or unreeling cable. This is also known as drum.
Wind Load The lateral pressure on a structure in pounds per square foot, due to wind blowing in any direction.
Wind Shake Wood cells in hardwoods of comparatively large diameter that have open ends and are set one above the other to form continuous tubes called vessels.
Windfall Tree(s) that have been uprooted or broken off by the wind. This is also known as blow down.
Winding Sticks Two narrow, thin, pieces of material whose edges are perfectly parallel when placed on each end of a work piece. The worker then sights across the top of them to determine if the piece is flat.
Windrow A long narrow pile, usually of logging slash removed from a planting site.
Witness Marks These are marks put on boards or pieces to keep them in order during gluing, joining, and assembly.
Witness Tree A tree used by surveyors to mark the location of a survey corner; the tree is located near the survey corner and is inscribed with survey data. This is also known as a bearing tree.
Wobbly Dado Head A single blade dado cutter where the blade is adjusted to wobble the width of the cut.
Wolf Tree A very large forest tree that has a wide-spreading crown and inhibits or prevents the growth of smaller trees around it
Wood Conversion The transformation of natural timber into any kind of commercial product. This includes all activities from commercial timber (log) delivery to the log yard at the initial commercial processing facility to the final product form offered for commercial sale as a consumer product.
Wood Failure The rupturing of wood fibers in strength tests of bonded joints usually expressed as the percentage of the total area involved that shows such failure.
Wood Flower Wood reduced to finely divided particles, approximately the same as those of cereal flours in size, appearance, and texture.
Wood rays. Strips of cells extending radially within a tree and varying in height from a few cells in some species to 4 inches or more in oak. The rays serve primarily to store food and to transport it horizontally in the tree.
Wood Substance The solid material of which wood is composed. It usually refers to the extractive-free solid substance of which the cell walls are composed.
Wood Wool Long, curly, slender strands of wood used as an aggregate component for some particleboards and cement-bonded composites.
Wood-Based Composite Panel A generic term for a material manufactured from wood veneer, strands, flakes, particles, or fibers or other lignocellulosic material and a synthetic resin or other binder.
Wood-Thermoplastic Composite Manufactured composite materials consisting primarily of wood elements and thermoplastic. The wood element may either serve as a reinforcement or filler in a continuous thermoplastic matrix, or the thermoplastic may as a binder to the wood element.
Workability The degree of ease and smoothness of cut obtainable with hand or machine tools.
Working Life The amount of time after mixing a glue or paint that it remains useable. Often used when referring to two-part epoxy and polyester glues.
Working Properties The properties of an adhesive that affect or distance the manner of application to the adherents to be bonded and the assembly of the joint before pressure application.
Wormholes Holes and channels cut in wood by insects.


X The drafting symbol for a cross section of an object.
X-Acto Knife This is a razor like blade in a handle. The blades come in various shapes, and are very handy for fine work.
Xylem The cellular tissues inside a tree’s bark; often called wood.


Yard The place where logs are accumulated.
Yard Lumber Lumber of those grades, sizes and patterns generally intended for ordinary construction and general building purposes.
Yarder A system of power-operated winches used to haul logs from a stump to a landing. This is also known as a donkey.
Yarder Wood Wood brought into a yard in the form of tree lengths, logs, or bolts, to be cut into shorter lengths.
Yarding of Unmerchantable Material Yarding of cull, rotten, small, or otherwise unusable wood material to be a designated area for disposal is written into the timber contract. This is required on all USDA Forest Service timber sale contracts.
Yarding Road A path followed by a turn of logs yarded by a cable method.
Yarding Tower Steel tower used on a steel spar skidder. A light-weight tower built on a tractor.
Yardstick A wooden rule 36” long.
Yellowheart Bright yellow heartwood Fine, straight grain
Yield The amount of product output recovered from a quantity of raw material input in forest product industries. Estimate in forest menstruation of the amount of wood that may be harvested from a particular type of forest stand by species, site, stocking, and management regime at various ages.
Yoke The heavy “U”-shaped part of a block by which the pulley is attached.


Zebrawood Light golden-yellow heartwood with streaks of dark brown to almost black interlocked grain
Zero Clearance Insert A blank insert for a table saw, the blade is raised up through it to create a kerf close to the sides of the blade.
Ziricote Various shades of black heartwood Irregular and wavy grain
Zoning Laws Laws adopted by local governments that restrict the location and type of new construction.