194 TRANSACTIONS OF THE i 
FORESTS IN RELATION TO CLIMATE 
AND WATER SUPPLY. 
BY J. CECIL ALTER.1 
The modifying influence of forests on climate makes 
them a refuge in winter for wild fowl and game animals, 
and a retreat in summer for domestic livestock, and 
vacation seekers. Without their coolness and freshness 
in summer the forests would be far less attractive as 
resort regions; and without their alleviating influence 
on winter storms there would be less haven for the wild 
life that inhabits them. 
Wind breaks have for many years been scientifically 
constructed about the farmsteads of the plains states. 
Smaller trees or large bushes are set to windward, and 
next to these are successive rows of higher varieties, the 
last line to the leeward being trees of some large type. 
This barrier causes the winds to glance aloft, and pro- 
vide shelter for livestock and the premises to the lee. 
Wind breaks and shelters composed of fruit and 
shade trees are carefully provided throughout the flatter, 
windier sections of Utah, where water is available. Some 
of the major projects in hand by certain commercial and 
development organizations in western Utah are the 
planting of trees to render the region more sheltered for 
birds, animals, and persons, in their meteorological 
aspects. 
The cooling influence of the forests, noted in the 
formation of local clouds at times, and in the down- 
drafts encountered by aviators, may extend several thou- 
sand feet aloft, but the horizontal cooling influence does 
not extend far outside the forest confines. 
This influence has been credited with causing pre- 
cipitation, but while the theory has a few arguments and 
factors in its favor, the influence is very slight. The 
forests in general exist where they do as a result of favor- 
iMeteorologist, United States Weather Bureau, Salt Lake City. 
