From their durable nature and great value, hardy, rapid-growing trees furnish 

 one of the most effective means of protecting land and crops. With the many 

 beneficial influences of windbreaks, must be considered a few influences that 

 are detrimental.- Fortunately, however, the undesirable features of properly 

 established windbreaks are of decidedly less consequence than the desirable 

 ones. The disadvantages, in fact, can be largely overcome by careful man- 

 agement. 



The extent of injury resulting from shading depends largely upon the power 

 of crops to tolerate shade. It appears to be much more detrimental to corn 

 than to alfalfa. Crop growth upon the strip of land in the immediate vicinity 

 of a windbreak is strongly influencedby the trees that feed upon the soil. 

 Within this area alfalfa generally succeeds better than do fruit trees or corn, 

 provided sufficient moisture is supplied for both the trees and the supple- 

 mentary crop. Diminished yields of crops in close proximity to windbreaks 

 can be offset by utilizing as much as possible of the space for headlands and 

 roads. Figure 1 shows the damaging effect of windbreaks upon field corn 

 and peach trees in locations where shading has effected only a slight influence. 



An accurate cash valuation cannot be affixed to windbreaks. This results 

 from variation not only in size and length of life of the trees, but also in the 

 value of crops and in the management of the adjacent land. 



Nature and Uses of Windbreaks. The term windbreak generally indicates 

 a closely planted row of trees, so located as to diminish the velocity of air 

 currents passing over an adjacent area of land. Large and elaborate wind- 

 breaks consisting of a number of rows of trees are frequently termed shelter 

 belts. Such windbreaks are usually developed by growing several kinds of 

 trees that range in habit from low-spreading types on the windward to very 

 tall trees on the leeward side. Rows of tall trees, being relatively permanent 

 and far apart, are the most practical and effective means of diminishing the 

 harmful effect of high wind velocity upon the success of field operations and 

 crop production. 



Windbreaks of secondary value are formed by various objects that retard 

 wind velocity near the ground. Among the most common are those established 

 by piling sage brush in windrows, by leaving strips of native vegetation standing 

 or by strips of tall, hardy crops such as rye or corn. The most effective pro- 

 tection for land is formed by low vegetation such as grass, rye, or alfalfa. 

 Its uniform distribution and close proximity to the surface of the soil dimin. 

 ishes the movement of air to a minimum. Neither of the low forms of wind- 

 breaks can be used successfully and economically under general farming con- 

 ditions. They need to be close together and consequently interfere with 

 systematic cultivation of the land. Windbreaks of this nature are valuable 

 for temporary use in reclaiming new land. 



As shelter of the most permanent and effective nature is afforded by prop- 

 erly developed windbreaks of trees, it is with this form only that the following 

 discussion deals. 



Various uses can be made of windbreaks. Among the most important 

 are the protection to fields, buildings, stock corrals, and feeding lots. Other 



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