State Board of Forestry. 



57 



below normal. It is now conceded hy scientists tliat it' any long 

 period changes are taking place they are of a secular nature, and, 

 therefore, not to be considered in a discussion of this character. 



The following graphic charts (Pigs. 2 and 3) represent the 

 mean temperature and annual precipitation, respectively, for the 

 State of Indiana for the twenty-four-year period, 1887 to 1910, in- 

 clusive. These records are compiled from all of the observations 

 made during that time at the regular and cooperative stations of 

 the United States Weather Bureau, which are about sixty in num- 

 ber. 



F 



1 



1 



1 



1 



f 



1 



1 



% 



\ 



^ 



1 



1 



\ 



^ 



1 



1 



1 



1 



1 



1 



1 



f 



1 



1 



v5^ 

 JO 

























































^ 



~> 







^ 





,^ 





^^ 





/^ 

















r^ 







\ 





y 



^ 



\ 













v.^ 









s 









> 









s 





\ 





/ 









y 





















X 





/ 1-- 







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fcL." 

































v^ 

































































Fig. 2. Mean temperature for Indiana, 1887-1910. 



Fig. 3. Average precipitation for Indiana, 1887-1910. 



In order to illustrate the regularity of the temperature and 

 rainfall elements during successive periods of years, the following 

 table has been prepared : 





1887-90 



1891-95 



1896-00 



1901-05 



1906-10 



Mean temperature ( ° F, ) . . 



..52.1 



52.3 



53.1 



51.5 



52.4 



Av. precipitation (inches) . 



..40.38 



37.32 



39.91 



37.75 



40.67 



This grouping into periods shows that while slight fluctuations 

 in temperature, and considerable ones in precipitation, have taken 

 place during successive periods, there is no permanent increase or 

 decrease indicated, and the variations are irregular as to the time 

 of their occurrence. 



Tlie effects of forests upon climate is a subject that has been 

 freely discussed, and various opinions prevail regarding the extent 

 and nature of their influence. Authentic records of observations 



