FORESTS OF KOCKY MOUNTAIN'S FOREST RESKRVI 



57 



computed ; by multiplication by the number of trees on the plots, the yields of the 

 plots at various ages were determined. The plots were classified according to site 

 and the average yields for each species of tree on each site were determined. An 

 eight-inch merchantable diameter limit was assumed. The factor of decimation was 

 neglected, but as decimation is not rapid after merchantable size is reached, the 

 effect is probably not great, since the yield is figured in board measure. It is also a 

 conservative factor since it tends to make the early yields light. The method would 

 not be entirely applicable to obtaining a table of yield in cubic feet. 



As the table is based on such a small area, and on measurements of mature 

 stands only, it can be considered as tentative only. It shows, however, the relation 

 between spruce and pine, and is believed to be near the truth. The plots taken are 

 fully stocked and about ' normal ' in the technical sense of that term. Large stands 

 will fall below the table in yield, as most actual stands are below normality. Normal 

 stands, however, give the truest data of the growth of a species. Studies of average 

 stands can in the future be made more rapidly and on a larger scale, but these tables 

 will obviate the necessity of gathering many of the classes of data which have been 

 used in their preparation. 



TABLE 12. 



VOLUME TABLE FOR ENGELMAXX SPRUCE. 

 (190 trees; top diameter, 5 inches; height of stump, 2-3 feet; Scribner log rule.) 



Height of Tree (Feet). 



Diameter 



at Breast - 



height. 



50 



60 



80 



90 



100 



Volume (Feet, Board Measure). 



110 



