220 ELEMENTS OF AGRICULTURE 



area of 167,976,886 acres. The establishment of these 

 forest reserves is chiefly due to President Cleveland and. 

 President Roosevelt. The object is not to prevent trees 

 from being cut. Forestry cuts trees and grows trees, 

 just as farming grows crops and harvests them. The 

 government reserves will furnish much more lumber than 

 would be produced if the reserves were lumbered over in 

 the usual manner, which leaves the forest practically 

 ruined and allows fires to complete the destruction. 



The chief object of the reserves is to protect the drain- 

 age basins of the streams that furnish water for irriga- 

 tion. This also prevents destructive floods and furnishes 

 a constant supply of water for water power. It also pre- 

 vents the destruction of the soil that occurs when moun- 

 tain sides are deforested. In such a case, it often takes 

 but a few years to wash away the soil that it has required 

 centuries to form. The reserves also maintain a constant 

 supply of wood and timber. A number of states also own 

 forest lands. Nearly every civilized government owns 

 forests. 



But the government reserves in the United States 

 cannot go far toward furnishing our future lumber supply. 

 The great bulk of our forest lands belong to individuals. 

 Most of the lumber supply must be furnished by private 

 citizens. 



208. Forests and Climate. Forests do not have a very 

 great influence on the heat of the surrounding region. 

 They modify the wind for short distances. Contrary to 

 popular opinion, they do not have any appreciable effect 

 on rainfall. Their great influence is in holding back the 

 waters that fall and so regulating the flow of streams. 



