248 DRY AND MESOPHYTIC FOREST COMMUNITIES 
of moisture of the atmosphere, decreased light, decreased temperature 
maximum in summer. The poisoning of the soil by root excretions 
and the modification of conditions on the ground brought about by a 
See ee 
Beet SRP 2cReaes 
Ps is 
Sel EeSaRashtes V J 
sR CPS REE 
Hi ARES AS SERRE RSE SN BRA 
BURRS eR PRES EeSeaRREe 
SRE EEA eR CEE 
i REL RREME: 
Bere Oak dinetosaese = seems 
Oe a ee BEEBE e aes 
SRR RRERUEREEEE eS oe 
Fic. 251.—Mean daily evaporation rates (c.c. per day) in the ground stratum of 
four of the animal communities (after Fuller). 
given set of trees are believed to prevent the germination of seeds of 
most of such trees, and at the same time to prepare the way for those of 
