Definitions for common timber and lumber industry terms.

As within any economic sector, the logging and forest-product industries have their own industry language, terms and nomenclature. Below is a list of some of the more common words and phrases you'll come across when dealing with the hardwood lumber industry.

Board Foot

A Board Foot is a unit of volume commonly used in the hardwood lumber and logging industries. It is equivalent to a piece of wood one foot wide, one foot long and one inch thick, or 144 cubic inches.


A lumber defect in which a board isn't flat lengthwise.


The process of cutting boards to length.

Butt Log

The first 8 to 16 feet of a tree trunk depending on quality. The Butt Log typically contains a majority of the value of a tree.


A squared off log.


Caused by improper drying. Board interior is under competing tension with board exterior. Casehardened lumber is typically no longer suited for most typical applications.


A timber harvesting method resulting in the indiscriminate cutting of all trees at a site, regardless of size, species or quality.


Trees which lose their leaves at the end of the growth cycle.


A machine for removing limbs from harvested trees.

Form Class

Gauges the straightness of trees contained in a stand.


A quality rating assigned to a wood product as specified by an independent grading authority.


Wood manufactured from broad leaf tree species'.


Lumber that has not been kiln-dried.


Wood from the inner portion of a tree. In most species heartwood is less desirable than sapwood. In a select few such as Hard Maple, the sapwood is actually more valuable.


Circular portion of a branch that becomes embedded in a tree as the trunk grows around it.

Log Rule

A scale used to quantify log volume. Doyle, Scribner and International are the most common log rules utilized in the US.


A value-added product produced by cutting trees into standardized, dimensional boards.


The core of a tree or branch.


Lumber that is sawn across annual growth rings resulting in rings that form between a 45 and 90 degree angle with the cut.


The fluid in a tree or log that contains nutrients taken up from the soil.


The outer portion of a tree or limb. It is the more active growth region and tends to be lighter in color than the heartwood.


Dark streaks in wood resulting from the introduction of a particular strain of fungus.


A veneer tree is a perfect specimen. They are tall, straight and knot/limb free. Veneer trees are sold to companies that peel the log like an apple, shaving off small fractions of an inch to be glued to less expensive wood and used in construction and furniture building.

Wood Pulp

Mechanically-ground wood chips and/or chemically digested at elevated temperatures to produce wood fibers useful in a wide array of manufacturing applications.