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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. 

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