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Industry Terms and Definitions

Below you can find a glossary of terms related to the lumber and timber industry to help you better understand SPTP’s products and services and how they can benefit your organization. 

Air dried

Seasoned by exposure to the atmosphere, in the open or under cover, without artificial heat

Annual growth ring

The layer of growth added to the circumference of a tree in one year, including both spring wood and summer wood

Band Mill

A sawmill using a toothed, endless steel blade for its saw


The outermost covering of a tree


A piece of lumber decorated with a raised half–circle bead along its length


A structural member, usually larger than five inches in width and thickness, used horizontally to support a load

Best Management Practices / BMPs

State or local regularity or non–regularity guidelines from protecting waterways as required by federal statutes including the Clean Water Act and the Water Pollution Control Act

Bevel Siding

A board that has been resawn diagonally to be used to clad the exterior of a building


A discoloration of wood caused by a fungus; usually occurring in the sapwood. It is particularly troublesome in Southern Yellow Pine logs during the summer months.


A piece of lumber less than two inches in nominal thickness and one inch or more in width

Board Foot

The basic unit of measurement for lumber; one board foot is equal to a one–inch board, twelve inches in width and one foot in length, thus, a ten foot long, twelve inch wide, and one inch thick piece would contain ten board feet; when calculating board feet, nominal sizes are assumed


An identifying mark on the end of a log indicating the owner of a log; the brand is made on the log by hitting the end with a hammer–like device that bears the design of the brand; also, there is paint sprayed on logs to indicate to the mill deck scaler which area the logs were from


The act of cutting a log to a specified length while attempting to maximize the log value


A person who saws felled trees into logs


The lower end of a tree, or a log from that part of the tree closest to the stump

Cambium Layer

A cell layer in the outer part of the tree that produces new wood for the growth of the tree; the cambium encloses the other living parts of the tree; cambial cells divide to produce wood cells on the inside of the cambium layer and phloam, or bark cells, on the outer side of the cambium


A large slab cut from a log at the head saw, usually having one or more rounded edges and destined for further processing by other saws

Cant hook

A wooden lever with an iron hook at the lower end, used in turning logs or cants; also, a cant dog

Cat face

A scar on a tree or log, caused by fire or injury to the growing tree

Center matched

Lumber that has been worked to contain a tongue in the center of one edge of each piece and groove in the center of the opposite edge, to provide a close, tongue–and–groove, joint by fitting the two pieces together

Center pull

Felled log; a large diameter splinter pulled from the butt of the log; defect
A document issued by a grading agency that assures the buyer that the shipment of lumber has been examined by a qualified inspector and that the lumber in the shipment is of the grade indicated; often used for selects and timbers where a grade mark would not show, or where one would affect the use of the piece


A lengthwise separation of wood, normally occurring across or through the rings of annual growth and usually the result of seasoning; classified for the purpose of grading as surface check, small, medium, or large, end check, and through check; surface check occurs on the surface of the piece, end check occurs on and end, and through check extends from one surface through the piece to the opposite surface


A small piece of wood used to make pulp; the chips are either made from wood waste in a sawmill or plywood plant or from pulpwood cut specifically for this purpose; chips are of generally uniform size, and are larger and coarser than sawdust

Chip n saw

A brand of chipping headrig; although this is one of several brands, the name has come into common usage as applicable to all such types of machines


Machine used to chip wood waste in a sawmill

Chromium Copper Arsenate (CCA)

Chemical preservative used when pressure treating Southern Yellow Pine


1. Free or practically free of all blemishes, characteristics, or defects 2. A select grade of lumber 3. A member in good standing of the International Workers of the World


1. A term applied to the board sizes 2. Lumber that is suitable for general construction and utility purposes 3. Equal or shared characteristics, such as a common joist, the joists in a single floor


Any of an order of mostly evergreen trees and shrubs, including those with true cones, such as pines, and with arillate fruit, such as yews


A unit of measurement equal to a stack of wood four–by–four–by–eight feet, or 128 cubic feet; yellow pine is often measured in cords whereby 2.78 tons is equal to one cord


A wood preservative consisting mainly of aromatic hydrocarbons obtained by distillation of coal tar; used to preserve wood products such as utility poles, fence posts, and the like that come into contact with the ground


To estimate the volume and quality of a timber stand by visual examination of test plots or strips in the stand; a cruiser usually examines from ten percent to 20 percent of the total stand


1. A tree or log that is less than one–third usable for lumber or plywood because of excessive decay or other defects; cull logs are often converted to chips for sale to pulp producers 2. Lumber of the lowest quality with little or no commercial value, usually below economy or Number 5 grade; lumber is sometimes purchased "mill run, culls out"

Custom milling

The surfacing or remanufacturing of lumber on a contract basis and to order; the lumber usually belongs to the person ordering the milling, with the mill receiving a fee for its services

Cut to length

Lumber, plywood or particle board sawn to a specific size, usually designated by the buyer; most often seen in items destined for remanufacture


Diameter at Breast Height


Double end trimmed; passed through saws to be smoothly trimmed at both ends, commonly in length increments of two feet


A machine used to remove bark from logs prior to processing them into lumber, panels, or pulp


Lumber used primarily for roofing and flooring applications; most common sizes of decking are: 5/4 X 6, 2 X 6, 2 X 8, 3 X 6, and 4 X 6; decking is often sawn with tongues and grooves and in various patterns (double tongue–and–groove and single tongue–and–groove); patterns are sometimes sawn on the face to be exposed; these patterns are often grooves or various shapes, depths and sizes


To remove limbs from trees before processing


A reference to the specific gravity of wood; lumber classified as "dense" has six or more annual rings per inch, plus one third or more summer wood, measured at either end; pieces averaging less than six rings per inch also qualify if the rings average one half or more summer wood

Design value

A measurement of strength in lumber involving the basic properties of wood; these are: fiber stress and bending (Fb), tension parallel to grain (Ft), horizontal shear (Fv), compression perpendicular to grain (Fcl), and modulus of elasticity (E)


The same as fall down; pieces that did not meet grade or size requirements in the manufacturing process

Draw knife

A carpentry tool consisting of a cutting blade with handles attached at each end; it is used by drawing it towards the body, with the cutting edge of the knife facing the user; it is used for rounding edges, reducing width or thickness of a board, etc


Low grade lumber or panels used to separate and bind ship cargos, stakes, strips or other pieces used to hold and protect merchandise during truck shipment; southern yellow pine lumber that is below number two grade but not lower than number four


Eased edge; a part of the planing or surfacing operation in which the edges of dimension and many other products are slightly rounded to reduce splintering; lumber of one and two inch nominal thickness may be rounded to a radius of no more than 1/16 and 1/8 inch respectively


A piece of sawmill machinery used to saw cants after they come off the headrig, squaring the edges and ripping the cants into lumber


Freight on board


To cut down a tree; a faller fells a tree, with a falling saw


A person who fells a tree with a chainsaw

Feller buncher

A self–propelled machine used to fell trees by shearing them off near the ground using a hydraulic apparatus; some models also strip limbs and "bunch" the logs for later pickup; the machines can be used on relatively level ground and are most common in the South

Field treatment

The application of wood preservative "in the field," as opposed to at a treating plant; such treatment is applied without pressure to cut ends, bored holes, and other newly–exposed surfaces of treated wood

File room

Room where saws and knives are sharpened


A saw filer; the person in a sawmill or logging operation who keeps the saws sharp


Fine milled chips used in production of particle board; fines are larger than sander dust or wood floor; the faces of particle board panels are made of fines, with coarser chips used to make up the inner parts of the particle board


1. A log sawn on two or more sides from which veneer is sliced 2. Thin layers of veneer sliced from a cross–section of a log, as opposed to turning the log on a lathe and peeling from the outer edge in a continuous ribbon; flitch veneers are often kept in order as they are sliced from a log; this provides a pattern to the veneer as it is laid up in panels; panels that are laid up with matching flitches are said to have a flitch pattern 3. A product cut from a log by sawing on two sides and leaving two rounded sides; usually exported from joinery


One who practices forestry; a person trained in forest management


The place on a tree where the stem separates into two pieces; usually known as a defect


Lumber used for structural members in a house or other building; a skeleton to which roofs, floors and sides are attached

Freight forwarder

One who accepts small lot shipments from shippers and combines them for forwarding in large lots; if international shipments are involved, a forwarder will attend to customs procedure and documents

Freight rate

The charge assesed by a freight carrier for moving a commodity from one point to another; rates vary by distance and the types of commodity and the methods of calculating rates differ among rail, truck, and ship carriers

Full cell process

A process for impregnating wood with preservatives or other chemicals in which a vacuum is created to draw air from the wood before admitting the chemical


Shorthand version of "Glue Laminated"


To examine lumber or timbers for strength, defects, appearance, etc. according to an established set of rules


A stamp or symbol indicating the grade, quality and or intended use of a piece of lumber, plywood, or other wood product; to be recognized as "grademarked," the product must bear an official stamp issued by a grading agency and applied by a qualified grader, or it must be accompanied by a certificate attesting to the grade


A worker who examines lumber, plywood, or other wood products and assigns it a grade according to an established set of rules; the grader is usually an employee of the mill, but sometimes is employed by a grading agency which charges the mill for his services

Grading agency

An organization that provides grading rules, gradestamps and supervisory services to member producers; the agency is financed by assessing users of the service a rate based on their production

Grading rules

A set of criteria by which to judge various pieces of lumber or plywood in terms of strength, appearance, and suitability for various uses; regional grading agencies draw up rules for grading based on the voluntary product standards issued by the U.S. Bureau of Standards


A general term referring to the arrangement, appearance, and direction of wood fibers. Among the many types of grain are fine, coarse, straight, curly, open, flat, vertical, and spiral; in paper making, the predominant direction in which the fibers are aligned


A heavy set of tongs developed primarily to eliminate large tong holes in logs; used with a log loader equipped with a heel boom for loading logs onto trucks


Unseasoned; not dry, lumber


(Hammerbrand) A mark on a log or timber that identifies the owner; a brand

Heart wood

The portion of the tree contained within the sapwood; this term is sometimes used to mean the pith; the heartwood is dormant and unnecessary for the tree's continued life; the living part of the tree is contained in its outer parts

Heavy dimension

A term sometimes used to describe squares and timbers four inches in thickness, such as 4 X 4, 4 X 6

Heavy timber

Rough or surfaced pieces having a smallest dimension of at least 5 inches

High temperature drying

A method of drying lumber using a dry bulb temperature in excess of 212 degrees F

Hit and miss

A series of surfaced areas with skips not over 1/16 inch scant between them


Cutting slits into the surfaces of a piece of wood prior to preservative treatment to improve absorption


A species of wood native to a particular area or region


Kiln dried after treatment; treated lumber that has been seasoned in a kiln to a predetermined moisture content following the treating process


The width of a saw cut; this portion of a log is lost as waste when it is sawn for lumber, although the residue can be used as fuel or for other purposes; the size of a kerf is dependent on saw thickness, saw type, sharpness and other factors


A chamber in which wood products are seasoned by applying heat and withdrawing air

Kiln charge

One full load for a kiln; the amount of lumber processed in a kiln

Kiln dried

Lumber that has been seasoned in a kiln to a predetermined moisture content

Kiln stick

A 1 X 1 1/4 piece used between layers of wood to improve air circulation within the bundle


A branch or limb embedded in a tree and cut through in the process of manufacturing; knots are classified according to size, quality, and occurrence


A collecting point for logs; the place to which logs are yarded for loading and transportation from the woods; a floor or platform between flights of stairs

Loblolly pine

Pinus Taeda; one of the southern yellow pines, this species takes its name from the fact that it often grows in moist depressions called loblollies; it is the fastest growing and most plentiful of the southern pines; the species is found in a range from Texas to Delaware

Log yard

The southern equivalent of a log staging or storage area


One who works in the woods performing any of a variety of jobs related to the harvesting of timber.

Longleaf pine

Pinus Palustris; this species is native to the southeast and Gulf Coast; commercially, it is grouped with other species as "southern yellow pine"; it is an important commercial species for lumber and plywood as well as for naval stores (turpentine, resins, etc.); it closely resembles slash pine


Long lengths

Low temperature drying

A process of drying by dehumidification by condensing the moisture removed from the lumber and recirculating the heated air


1. A wood product manufactured from logs by sawing, resawing, and, usually, planing, with all four sides sawn; "Timber" is used in place of "lumber" in many countries 2. To log or to manufacture lumber

Lumber yard

A retail outlet selling lumber and, usually, other building materials; a storage area at a saw mill

Marine borers

Mollusks and crustaceans that destroy wood piling used in supporting wharves, piers, and other structures that are more or less in constant contact with salt water; mollusks bore into the wood for food and shelter, while the action of crustaceans is usually on or near the surface of the wood; creosote treatment or a covering of the wood, are the usual means of combating marine borers


The standard abbreviation for 1000 board feet of standing timber, logs or lumber


The person in a sawmill or plywood plant who maintains and repairs machinery and other equipment


One million board feet

Moisture content

The weight of the water in wood, expressed as the percentage of the weight of the wood

Moisture meter

A device used to measure moisture content

Niche product

A product that is manufactured and marketed for specialized uses; niche products are readily differentiated from other products

Nominal size

The size designation for most lumber, plywood and other panel products, used for convenience; in lumber, the nominal size usually is greater than the actual dimension; thus, a kiln dried 2 x 4 ordinarily is surfaced to 1.5 to 3.5 inches; in panel products, the size is generally stated in square feet for the surface dimension in increments of 1/ 8 inch for thickness


A reference to the specific gravity of wood' lumber classified as "non–dense" has five or fewer annual rings per inch, and/or less than 1/3 summerwood, measured at either end

Novelty siding

Siding with a lower edge intended to be decorative

On the stump

Timber or standing tree that has not yet been felled


A chemical used in wood preserving; it is usually applied under pressure so that it will penetrate the wood


Precision end trimmed; lumber trimmed square and smooth on both ends, to a uniform length with a manufacturing tolerance of 1/16 inch over or under length in a maximum of 20% of the pieces


Round timbers or poles that are driven into the ground to support a load, as a foundation for a structure, or as part of a dock or moorage


Any of the various softwoods of the genus Pinus

Pine beetles

Insects that bore into the bark of pine trees to lay eggs; the larvae of the beetle feeds off the cambium layer of the tree, eventually killing it


1. An accumulation of resign in the wood cells in a more–or–less irregular patch; classified for grading purposes as light, medium, heavy or massed 2. The angle or inclination of a roof, which varies according to the climate or materials used 3. The set, or projection of teeth, on alternate sides of a saw to provide clearance for its body


The small, soft core in the structural center of a log


A machine used to surface rough lumber or timber

Planing mill

An installation where lumber is surfaced; also refers to mills where lumber is remanufactured to a customer's specifications


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 angles to the one adjacent to it; the veneer sheets are united, under pressure, using a bonding agent


A long, usually round, piece of wood, often a small diameter log with the bark removed, used to carry utility wires or for other purposes; often treated with a preservative


A lumber item that is cut to a precise length at the time of manufacture so that it may be used in construction at the jobsite without further trimming


Lumber that has been drilled at the mill to accommodate bolts or other hardware


Any substance applied to wood that helps it resist decay, rotting or harmful insects

Pressure treating

A process of impregnating lumber or other wood products with various chemicals, such as preservatives fire retardants, by forcing the chemicals into the structure of the wood using high pressure


A grade of finished lumber, ranking below superior, the highest grade, and above E, the lowest grade of finished; finished graded prime must present a fine appearance and is designed for application where finishing requirements are less exacting


Wood used to produce pulp used in the manufacture of paper products; pulpwood is usually wood that is too small, of inferior quality, or the wrong species to be used in the manufacture of lumber or plywood

Radius edge decking

A board of nominal 5/4 thickness with rounded edges the length of one surface; most frequently manufactured from southern pine or cedar, it is used primarily for construction of exterior decks on residential homes

Random length

A designation that indicates that lumber so labeled contains an assortment of widths and lengths; although all types of lumber may be packaged and sold in this manner, it is more common in the marketing of boards than in dimension or other lumber items; it is particularly common in the marketing of Idaho white pine, and shop of various species

Random width

1. Wood products of various widths 2. Veneer clipped in various non–standard widths, usually less than two feet wide 3. Shingles or shakes that are manufactured and sold in various widths within a certain length, thickness and grade 4. Lumber, usually for factory or industrial uses, that is sold in random widths


The regrowth of plants and trees in an area that has been logged or burned


1. To saw a piece of lumber along its horizontal axis 2. A band saw that performs such an operation

Rough lumber

Lumber which has not been dressed or surfaced but has been sawn, edged, and trimmed


Surfaced one side and one edge


Surfaced one side and two edges


Surfaced two edges


Surfaced two sides


Surfaced two sides and one edge


Surfaced four sides


The outer layers of growth between the bark and the heartwood that contain the sap


Small particles of wood removed by the saw in cutting


Log category used for sawing lumber and timbers


A manufacturing plant in which logs are converted to lumber by running them through a series of saws


1. A worker in a sawmill who operates the headrig, or main saw, making the initial cuts on a log 2. In the early logging days, one who felled trees and sawed them into logs; these workers are now called fallers and buckers, respectively

Scale ticket

Weight ticket; a tag attached to the end of a log after it has been scaled; information obtained from scaling the log is written on the ticket


The process of evaporation and extraction of moisture from green or partially dried wood


A wall of embankment designed to prevent encroachment from the sea; can be made of wood, masonry, earth, or a combination of materials

Seed tree

A tree left standing in a logging operation to provide seed for natural regeneration of the logged–over area


1. A high–quality piece of lumber graded for appearance; select lumber is used in interior and exterior trim, and cabinetry; it is most often sold S4S in a 4/4 thickness but may also be produced S2S in a variety of thicknesses usually for remanufacturing 2. A grade of Canadian exterior plywood


1. A lengthwise grain separation between growth rings, or a break through the rings (radial shake), usually the result of high winds; among the recognized types and degrees of shake are: fine, slight, medium, open, cup, round, ring, shell, through, and pith 2. Roofing material produced from wood (most often a Cedar); shakes have at least one surface with a natural grain textured split surface


A very thin slice of wood that is produced when planing lumber and timbers


1. Lumber that has been worked to make a lapped, or rabbeted joint on each edge so that pieces may be fitted together snugly for increased strength and stability 2. A similar pattern cut into plywood or other wood panels used as siding, to assure a tight joint


The theory and practice of controlling the establishment, composition, care, and development of stands of trees to achieve the objectives of management


A mechanized piece of logging equipment used to drag, or skid, logs from the cutting area to the landing; skidders usually have wheels and rubber tires, rather than endless tracks such as those found on crawler tractors


The exterior portion of a log removed by the saw, having one flat and one curved surface


Debris such as limbs, bark, broken pieces of logs, etc., left over after a logging operation

Slash pine

Pinus Elliottii; one of several pine species grouped under the designation of southern yellow pine; slash pine is native to the southeastern and Gulf coast states; it is fast growing and matures early; its wood closely resembles that of the longleaf pine a member of the SYP group

Slasher saw

A type of reciprocating saw used for cutting logs to length


A standing dead tree or portion of a tree from which most of the foliage, limbs, etc., have fallen

Southern yellow pine

A species group composed primarily loblolly, longleaf, shortleaf and slash pines; various subspecies also are included in the group; the southern yellow pine region refers to the southeastern United States, from Texas to Virginia


An identifiable group of trees or section of timber occurring in a particular area


1. Material carried in inventory for resale 2. To purchase materials for inventory; to stock up 3. The main stem of a tree


A horizontal timber used to support floor joists or other cross members


Refers to lumber that has been dressed by a planing machine for the purpose of attaining smoothness of surface and uniformity of size; surfacing may be done on one side or edge, or all sides


A marine borer that damages untreated wood by drilling holes in it


Insects that destroy wood by eating the wood fiber; termites are social insects that exist in most parts of the US; they are most destructive in the coastal states and the Southwest; termites can enter wood through the ground or above the ground, although the subterranean type is most common in the US; they eat the softer springwood first and prefer sapwood over heartwood


1. Standing trees, stumpage 2. A size classification of lumber that includes pieces that are at least five inches in their smallest dimension; also classified as beams, stringers, girders, etc. 3. In the British and Australian trades, this term is used to describe all sizes of lumber


The top of a pole or piling

Tongue & groove

Lumber machined to have a groove on one side and a protruding tongue on the other so that pieces will fit snugly together, with the tongue of one fitting into the groove of the other

Treating plant

An operation where wood products are treated with preservative or fire retardant

Trim saw

A set of saws, usually circular, used to cut lumber to various lengths by lowering individual blades to make contact with the lumber as it passes beneath the saws on a moving chain


Treating service only; a company that treats wood products for others for a fee


(V-groove) A pattern applied to tongue and groove lumber in which the edges of the pieces are clamped so that a v-shaped groove is formed on the surface where the 2 pieces meet

Veneer log

A log used in the manufacture of veneer "a peeler" (plywood)


Bark, or the lack of wood from any cause, on the edge or corner of a piece of lumber; in plywood, thin to open areas in veneer sheets that result from outer log surface irregularities

Waterborne preservative

Preservative salts in a water solution that are transferred to the wood during the treating process


Low lying areas of land such as marshes that are saturated with water for extended periods; they are considered beneficial for wildlife, plant diversity, flood control, and pollution filtration; they are often protected by various regulations that govern use, building, etc


The wider widths of dimension lumber or timber usually ten or twelve inch widths; a speciality mill may produce it up to 20" wide

Widowmaker (buckskin)

A limb that poses danger to a logger through the possibility of it falling from a tree and hitting him


The amount of product recovered from a given quantity of raw material