i8 



TREE GROWTH AND RAINFALL — CLOCK 



41 



available, the rainfall records of Albuquerque and Las Vegas corrob- 

 orate the results obtained by the use of Santa Fe rainfall. 



For the rainfall of the period 1898-1941, against the period 1850- 

 1897: amount of rainfall increased; and average variation, average 

 departure, and average departure from mean variation decreased. 



Cumulative Tree Growth and Rainfall 

 Percent Variations 



IN Hundreds (Ratio Scale') 



Groups 4, 10 



850 



1870 1890 1910 1930 



950 



Fig. 7.— Cumulative variations of tree growth and rainfall. Trees in groups 

 5 and ii were from wet sites and those in groups 4 and 10 chiefly from dry 

 sites. 



For group 11 contrasted in the same manner: average variation, 

 average departure, and average departure from mean variation de- 

 creased ; and correlation with rainfall increased to an extent compa- 

 rable to that with Chacon rainfall considering the much greater 

 distance. 



