TREE GROWTH AND RAINFALL— CLOCK 



19 



matter of trend agreement appears to be another facet of the general 

 problem brought out by the changes of characteristics on the wood 

 through the years from 1850 to 1941. 



Table 8. — Hohnan Pass collection 

 Characteristics 



1850-1S97 1898-1941 



Average variation 



0.40 



G 10 0.26 



II 0.38 0.27 



7 0.21 0.27 



Average thickness 



G 10 1.53 1.70 



II 2.26 1.96 



7 1.90 1.83 



Average departure 



G 10 0.32 0.36 



II 0.34 0.30 



7 0.18 0.20 



Average departure from mean variation 



G 10 0.132 0.148 



II 0.204 0.118 



7 o.iio 0.105 



STUDY OF RAINFALL CHARACTERISTICS 



Two tasks were set out for consideration in connection with the 

 rainfall data: (i) to determine the interrelationships among the 

 stations of usable records in the vicinity of Holman Pass and (2) to 

 determine the characteristics of those records. As to the first task, 

 it is necessary to know the extent of the differences between two 

 adjacent stations in order to appreciate and allow for the possible 

 differences between the trees and the station nearest to them. As to 

 the second task, it is desired to learn whether or not the rainfall shows 

 any differences between the two periods 1850-1897 and 1898-1941, 

 and, if it does, to compare the differences with those obtained from 

 a study of growth-layer sequences. 



