Terminology

The U.S. Forest Service forest inventory data are reported using very specific terminologies. Relevant definitions used in the summary below are:

timberland

forest land capable of producing 20 cu.ft. of industrial wood per acre per year, and not withdrawn from timber production.

sawtimber volume

volume of timber (expressed in International 1/4-inch log rule) meeting minimum standards of diameter, length and defect in softwood trees $9.0^{\prime \prime}$ DBH (diameter breast height) and larger in logs at least $8^{\prime}$ long with a minimum diameter of $6^{\prime \prime}$ inside bark, and in hardwood trees $11.0^{\prime \prime}$ DBH and larger with minimum log diameters inside bark of $8^{\prime \prime}$.

growing stock volume

the volume of sound wood (expressed in cubic feet) from a $1^{\prime}$ stump to a $4^{\prime \prime}$ diameter-outside-bark top, in living trees $5^{\prime \prime}$ DBH and up, of commercial species with potential to produce at least 1, $12^{\prime}$ or 2, $8^{\prime}$ saw logs. (This category includes sawtimber volume too.)