Crown Space of JVcstern Yellow Pine. 



337 



are from 12 to 20 inches are not suppressed by the crowns of 

 other trees of the same species and of similar size, if the edges 

 of the crowns are separated by a space of from 5 to 10 feet. 

 In the same way trees having a D. B. H. of from 22 to 32 inches 

 require a space of 10 to 15 feet between the edges of their 

 crowns, and, for trees 34 inches D. B. H. and over, a propor- 

 tionately larger space, say of 15 to 20 feet is required. 



This extra distance between the crowns should then be added 

 to the diameter of the crowns shown in Table II, to obtain the 

 total distance at which the trees should be separated frorri one 

 another. 



The crowns of trees are in reality circular, but for the sake 

 of insuring a conservative estimate, they will be considered as 

 square. Thus the number of dominant trees of any D. B. H. 

 class which it will be possible to grow on an acre can be deter- 



TABLE IV. 



Western Yeulow Pine. 

 Relation of Crown Space, Number of Trees and Volume. 



mined by squaring the figures given in Table III representing the 

 distances at which the trees are spaced, and dividing the result- 

 ant product into 43,560, which is the number of square feet in an 

 acre. From these calculations the table IV could be constructed, 

 adding ages and volumes from other compilations in the District 

 office. 



