Growth and Mortality by Ownership Group 



Growth Commercial timberlands on state and private lands in Working 

 Circle 3 were growing at an annual rate of 37,124,000 net cubic feet or 

 107,218,000 net board feet Scribner (see Tables 8 and 9). Over time, net 

 growth will change depending on such factors as the forest's overall age, 

 condition, mortality rates, and the amount of harvest. 



Most of the cubic foot and board foot net growth — about 70 percent — 

 took place on the other private owner group's timberland. Net growth in 

 cubic feet per acre was highest on timberlands owned by the state and other 

 public ownership group. Net growth in board feet per acre was highest on 

 timberlands owned by forest industries (see Table 12). Trees on an average 

 acre of timberland in Working Circle 3 grew 31.5 net cubic feet or 102 net 

 board feet Scribner per year. 



Mortality The data shows that state and private timberlands in Working 

 Circle 3 lose 5,515,000 net cubic feet of growing stock or 13,562,000 net 

 board feet of sawtimber annually due to natural mortality (see Tables 10 and 

 11). This timber is removed from the commercial growing stock by natural 

 causes such as insects, disease, fire, and weather. Timber removed through 

 logging is not considered when computing mortality figures. 



On a per acre basis, mortality rates appear to be highest on forest in- 

 dustry-owned lands and lowest on other private timberlands (see Table 12). 

 The average annual mortality rate in the working circle was 4.7 cubic feet of 

 growing stock per acre, or 12 board feet Scribner per acre for sawtimber. 



Table 10. Net annual mortality of growing stock on commercial softwood and 

 hardwood forest types by ownership group, Working Circle 3 

 (thousand cubic feet) . 



Forest Type 



Ownership Group Softwood Types Hardwood Types Total 



thousand cubic feet 



State and Other Public 669 29 699 



Forest Industry 1,817 1 1,818 



Other Private 2,841 157 2,998 



All Owners 5,327 188 5,515 



-28- 



