198 



JOURNAI, OF FORESTRY 



giving the backward trees the opportunity of overtaking the leaders. 

 Sometimes in this way trees which would normally have been forced 



10 20 30 40 SO 60 70 80 90 104 



PERCENT INJURED PER ACRE 



Fig. 4. — Relation of density to the per cent of trees injured per acre 



out by natural selection succeed in establishing themselves as dominant 

 trees. This interference with normal development reduces the rate of 

 growth for the stand as a whole. 



