116 



most severe from the standpoint of moisture requirements as 

 compared with other forested areas. Under such circumstances, 

 therefore, we should expect to see most clearly expressed the 



F-G. I. Part of the crown of a young pine {Pinus ponderosa), showing the height 

 growths of the years 1910 to 1913 inclusive. 



influence of any variation in the moisture supply from time to 

 time, and especially from year to year. 



The relation of the water supply to metabolism and assimil- 



