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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. 


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