EFFECT OF FORESTS ON TEMPERATURE. 



59 



Second. The waste from the trees and from certain 

 plants which o-row only in their shade forms the forest 

 tloor, which has much to do with the movement of 

 water on the ground and within it. The influence of 



Fig. 40.— The forest floor. Idaho. 



the forest cover and the forest floor appears in the 

 temperature of the air, the evaporation of water, the 

 rainfall, and the course of the rain water after it has 

 reached the earth. 



EFFECT OF FOREST COVER OX TEMPERATURE. 



So far as the influence of the forest is concerned, the 

 temperature of the air is affected chieflv by the forest 

 cover. The leaves, which compose the greater part of 



