Area by Site Class 



Commercial timberland was placed in one of five productivity classes (see 

 Tables 13 and 14). As shown in Table 14, almost half of the timberland — 46 

 percent — had the potential to produce from 50 to 84 cubic feet of timber per 

 acre per year. An almost equal amount of timberland had the potential to 

 produce from 20 to 49 cubic feet of timber per acre per year. An average 

 sampled acre of commercial timberland had the potential to produce 54 cubic 

 feet of timber per year. This is below the average potential yield for the 

 entire United States — 74 cubic feet per acre per year — and slightly below 

 the Rocky Mountain region's average of 60 cubic feet per acre per year 

 (USDA Forest Service 1973). (Average potential productivity for the differ- 

 ent forest types in Working Circle 3 is shown in Table 23, page 45). 



Table 14 indicates the forest industry-owned timberlands had the highest 

 average potential productivity when compared to the other ownership groups. 



Table 11. Net annual mortality of sawtimber on commercial softwood and hard- 

 wood forest types by ownership group. Working Circle 3 (thousand 

 board feet Scribner) . 



Forest Type 



Ownership Group 



State and Other Public 

 Forest Industry 

 Other Private 



Softwood Types Hardwood Types 



thousand board feet 



1,372 83 



5,071 5 



6,547 485 



Total 



All Owners 



12,989 



572 



13,562 



Table 12. Net annual mortality and net and gross growth per acre for commer- 

 cial softwood forest types by ownership group. Working Circle 3 

 (cubic feet and board feet Scribner) . 



Ownership Group 



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