Annual Volume Growth Estimation 



As with the stand vohinie per acre equations, growth rates can be 

 predicted by easily measured variables that are representative of the 

 entire stand. Periodic annual cubic-foot and board-foot-volume growth 

 per acre were obtained from 9-year growth data. 



Gross and net periodic annual cubic-foot, and gross and net peri- 

 odic annual board-foot volume growth per acre were developed to pre- 

 dict growth rates. In determining these growth equations, several mod- 

 els were considered that were compatible with equations from growth 

 studies of other eastern conifers (Clutter, 1963 and Nelson, 1963). Net 

 volume growth constitutes 9-year volume of the live trees minus the 

 initial volume; gross volume growth constitutes 9-year volume of the 

 live trees plus the volume of the mortality trees minus the initial vol- 

 ume. Gross volume growth can also be expressed as that volume growth 

 of only those trees that live. 



Periodic annual net growth and periodic annual gross growth can 

 be represented by the equations: 



Periodic annual 

 net growth 



Periodic annual 

 gross growth 



Periodic annual 

 gross growth 



(9-year volume of 

 surviving trees) 



(Initial volume 

 of all trees) 



(9-year volume of 

 surviving trees) 



(Initial volume of 

 trees that survived 

 — at 9 years) 



or 



(9-year volume of 

 surviving trees) 



+ 



(Initial volume of 

 trees that died 

 in 9-year period) 



(Initial 

 volume of 

 all trees) 



Gross volume growth is a more realistic measure of potential wood 

 yield than net volume growth because one would expect to conduct 

 thinnings that would utilize the losses of mortality. 



