THE PRINCIPLES OF FORESTRY 163 



streams the water is greatly retarded and no flood is expe- 

 rienced. The water from heavy rains is held back by the 

 carpet of leaves on the soil beneath the trees, by the roots 

 in the soil, and by the decaying matter from former years. 



In sections where the forests have been cut off for the 

 use of man, the streams frequently go dry during the summer. 

 Water power of mills and factories is thus cut off; the water 

 supply for homes, villages, and cities is reduced to the danger 

 point. Navigation of the larger streams is checked or stopped 

 for a while. Many wells are without drinking water because 

 the level of the soil water is deeper than the wells. 



The growth of forests would correct the difficulty of water 

 supply in many parts of the country. The United States 

 Government has reserved large areas of mountainous and 

 hilly land for the purpose of preserving the natural forests and 

 maintaining the flow of the larger streams in those sections. 



Forest Planting on the Farm. — The wood-lot or forest 

 plantation on a farm where the land is all tillable should 

 usually be in the form of a wide shelter-belt. If there be 

 rough land on the farm not suitable for the more common 

 crops, groves may be maintained on this to good advantage. 

 On land too stony or too steep for use of other crops some 

 kinds of trees will grow well. The location of such groves is 

 to be determined by natural conditions. 



The location of the wide shelter-belts will be influenced 

 by several things. These trees may affect the air drainage 

 of near-by orchards; the wind currents will be controlled; 

 and the humidity of the air about the home will be influenced. 



Such trees should be far enough from the buildings and 

 roadways to not cause the drifting of snows which would be 

 in the way. The shelter-belt should be about six rods wide, 

 made up of a number of lines or rows of trees with the smaller 

 kinds on the side toward the prevailing wind. This will 

 deflect the wind currents upward and prevent their bad 

 effects. 



