GROWTH 



In estimating timber growth the possible sources of error,, in 

 addition to those cited under "area" and "volume , M include 

 errors in measuring increment cores, in reconstructing tree 

 volumes, and in dating mortality All practical efforts were 

 made to eliminate errors from these sources. Growth estimates 

 for the portion covered by complete survey are believed to be 

 somewhat low. As mentioned under "methods," the original growth 

 calculation for this portion of the State excluded approximately 

 one third of the commercial area where the stands were in a more 

 or less static condition with regard to volume. It appears now 

 that there may have actually been some net growth in these 

 stands during recent years. 



For the area sampled, standard errors of net growth are ± 8„4 

 percent or ± 11 million cubic feet for primary growing stock, 

 i 15 percent or t 36 million board feet for live saw-timber 

 trees . 



Actual growth for the State as a whole is judged to lie between 

 limits as follows 



Estimates of commodity drain are based chiefly on a complete tabu- 

 lation of production and consumption statistics, adjusted for 

 waste on the basis of woods and mill studies. Only 18 percent of 

 the cubic-foot and 12 percent of the board-foot drain are based on 

 sampling. The translation of production statistics into drain, 

 however, introduces an indeterminable error. The commodity drain 

 estimates for the State as a whole are judged to be between 90 

 and 100 million cubic feet of primary growing stock and between 

 520 and 550 million board feet of saw-timber volume. 



Million 



Gross growth primary growing stock 

 Net growth primary growing stock 

 Gross growth live saw-timber trees 

 Net growth live saw-timber trees 



290 to 320 cu. ft. 



240 to 280 cu. ft. 



840 to 930 bd. ft. 



600 to 700 bd. ft. 



COMMODITY DRAIN 



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