40 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



April-May rainfall for the period 1898-1941 over that of 1850-1897. 

 Again, figure 6, showing the charted correlations of group 7 with 

 Santa Fe rainfall for 1850- 1897, shows the emphasis to be on spring 

 rainfall. These relationships emphasize the multiple nature of growth 

 factors and the complexity of the problems involved. 



Before the contrasts between the periods 1850-1897 and 1898-1941 

 are summarized, mention should be made of two points, one having 

 to do with the incidence of opposed trends and the other with 

 cumulative variations. First, the incidence of opposed trends was 

 calculated for each lo-year interval for several of the groups against 

 the various rainfall intervals. In the case of groups 7, 10, and 11 

 compared with March- July rainfall the incidence of opposed trends 

 shows a general decline from early to recent years. The same is 



Table 21. — Santa Fe temperatures 



1874-1897 1898-1930 1910-1930 

 March 



Average 39-9 394 39-0 



Maximum 51.4 50.5 50.1 



Minimum 28.0 28.4 27.9 



April 



Average 47-4 46-75 46-5 



Maximum 60.0 58.45 58.2 



Minimum 34.76 35.1 34.8 



Majf 



Average 56.5 55-1 55-5 



Maximum 69.4 67.2 67.7 



Minimum 43.5 43.0 43.3 



true, in fact, for all rainfall intervals except that for March-April 

 in which the incidence increases from 1850 to 1941, thus agreeing 

 with the decrease of tree growth-rainfall correlation. Second, figure 

 7 gives the plotted cumulative variations of Santa Fe March-July 

 rainfall and certain tree groups. Groups 5 and 11 and groups 4 and 10 

 were each combined into one graph because the separate graphs very 

 nearly coincided. If groups 4 and 5 had been omitted there would 

 have been no change. The graphs illustrate the close correspondence 

 between the variations of Santa Fe rainfall and the variations of tree 

 growth as represented by group 1 1 which contains the trees from the 

 wetter sites. 



The various tables have brought out the contrasts between the 

 periods 1850-1897 and 1898- 1941. These may now be summarized 

 in respect to March-July rainfall at Santa Fe. In so far as data are 



