Studies in Prairie and Woodland 



43 



and herbaceous as well as in the fungus flora, each community 

 as it becomes temporarily stabilized sorting out the particular 

 population best adjusted to the particular set of environmental 

 conditions. 



Repeated light determinations at the several stations showed a 

 diminution in the following sequence: prairie i.oo; bur oak 0.06; 

 black oak 0.05 ; red oak 0.028 ; linden 0.02. 



SOIL MOISTURE 



Typical stations were selected in each of the preceding com- 

 munities and in that portion of the area included in the transects 

 as follows : 



Prairie station ; in the prairie on the knoll shown in figure 2 : 

 bur oak station ; at the crest of the hill on the right shown in 

 figure I : black oak station ; near the top of the slope shown at the 

 left in figure i : red oak and linden stations were selected in their 

 respective communities as shown in figure 2. 



At each of these stations soil moisture was determined at the 

 intervals and to the depths indicated respectively in the following 

 tables : 



TABLE 6 



The Available Water Content to a Depth of 12 Inches in the Several 

 Forest Communities at Peru, 1917 



An examination of these data reveals the fact, that with the 

 exception of the black oak habitat which is almost throughout 

 uniformly drier, that in the main there is an increasingly avail- 

 able soil moisture parallel with the direction of the succession. 



49 



