356 



GROWTH OF TREES IN DIAMETER 



Diameter growth based upon age is used, in practical studies, princi- 

 pally as an aid in indicating the difference in rate of growth of species, 

 sites, and different methods of treatment and as an aid in determining 

 the average age of stands in the forest under different conditions. 

 This application is much more limited than is commonly supposed 



20 30 



Age, Years 



Fig. 72 - 



-Differentiation of diameter growth as result of different rates of develop- 

 ment of crowns, in normal stands, even-aged. 



since for many problems the substitution of yields per acre based directly 

 on total age answers the questions more directly and accurately, while 

 for forests in which the average age for stands cannot be ascertained, 

 diameter growth is not based on total age, but on diameter classes 

 (§ 336). 



