CLIMATE AS INFLUENCED BY THE FOREST. 127 



XIII. CLIMATE AS INFLUENCED BY 

 THE PRESENCE OF THE FOREST. 



"WHEN sunshine falls on an area covered by trees, 

 the heat is more thoroughly absorbed or taken in 

 than when it falls on an arid or uncovered surface. 



The more thorough absorption of heat by a 

 wooded area is caused mainly as follows : 



1. The greater extent of surface presented by a 

 wooded than by an unwooded area, not only by 

 the trees themselves, but often also by the under- 

 brush which exists in most forest regions. 



2. The porous and better absorbing character 

 of the carpet of leaves that generally covers the 

 ground in forest regions. 



3. The presence of a greater amount of moisture 

 in the air of a forest region than in a region that 

 is void of vegetation. 



The marked increase in the area of a surface 

 covered by a forest over that of an equally large 

 unwooded surface would itself, apart from any 

 other circumstances, necessitate a smaller rise or in- 

 crease of temperature in the forest than would the 



