Rotten trees . — Live trees that do not contain at least one 12- foot saw log or two 

 noncontiguous saw logs, each 8 feet long or longer, now or prospectively, and/or do not meet 

 Rocky Mountain regional specifications for freedom from defect primarily because of rot; that is, 

 when more than 50 percent of the cull volume (cubic-foot basis) in a tree is rotten. 



Salvable dead trees . --Standing or down dead trees that are considered merchantable by Rocky 

 Mountain regional standards. 



Saw-log portion .--That part of the bole of sawtiraber trees between the stump and the saw- log 

 top. A 1-foot stump is used. 



Upper-stem portion . --That part of the bole of sawtimber trees above the saw- log top to a 

 minimum top diameter of 4.0 inches outside bark or to the point where the central stem breaks 

 into limbs, whichever occurs first. 



Tree Size Classes 



Seedlings . --Live trees less than 1.0 inch in d.b.h. 



Saplings . --Trees 1.0 to 4.9 inches in d.b.h. 



Poletimber trees . --Trees at least 5.0 inches in d.b.h., but smaller than sawtimber size. 



Sawtimber trees . — Trees exceeding poletimber size. In the Intermountain States, the minimum 

 d.b.h. for softwood sawtimber is 9.0 inches and for hardwoods 11.0 inches. 



Volume 



Cull volume . --Portions of a tree's volume that are not usable for industrial wood products 

 because of rot, form, or other defect. 



Net volume . — Gross volume less deductions for cull. 



Growing stock volume . --Net volume in cubic feet of live sawtimber trees and live poletimber 

 trees from stump to a minimum 4.0-inch top (of central stem) outside bark. Net volume equals 

 gross volume less deduction for rot and missing bole sections. 



Sawtimber volume . — Net volume in board feet of sawtimber trees of commercial species. Net 

 volume equals gross volume less deduction for rot, sweep, crook, and other defects that affect 

 use for lumber. 



Components of Change 



Net annual growth . — The increase in net growing stock or sawtimber volume of a specified 

 size class for a specific year. (Components of net annual growth include the increment in net 

 volume of trees at the beginning of the specific year surviving to its end, plus the net volume 

 of trees reaching the size class during the year, minus the net volume of trees that died during 

 the year, minus the net volume of trees that became rough or rotten trees during the year.) 



Mortality . --Number or sound-wood volume of growing stock trees dying from natural causes 

 during a specified period, usually annually. 



Removals . --The net volume of growing-stock or sawtimber trees removed from the inventory by 

 harvesting; cultural operations, such as timber stand improvement; land clearings; or changes in 

 land use. Includes the unused portion of growing stock or sawtimber trees cut or killed by 

 logging. 



