12 AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS. 



the supply of available soil moisture over the protected area. Crop 

 yields are thus increased. Investigations by the United States Forest 

 Service show that yields on protected areas have been increased 35 

 per cent above normal. In one instance a well protected field of corn 

 made a net gain above normal yield equivalent to the product from an 

 area as long as the windbreak and twice as wide as the height of the 

 trees. Statistics further show that areas protected by windbreaks have 

 produced crops under the most severe growing conditions when crops 

 on unprotected areas under the same conditions were failures. When 

 high winds occur shelterbelts prevent breakage of crops and orchard 

 trees as well as the burying of field crops under loose, fine soils which 

 may be transported by the wind. The protection afforded stock has 

 already been mentioned. 



The wood products obtained from thinnings made in the windbreak 

 are further advantages which should not be overlooked. It is obvious 

 the cuttings cannot be made too heavy, but with care the windbreak can 

 be made to furnish a large part, if not all, of the material used on 

 the farm. 



Eanch buildings are made more habitable when protected from the 

 blasts of hot and cold winds. A quite intangible, but none the less 

 real, value of the windbreak is the aesthetic one. Who can estimate 

 the value of personal comfort and satisfaction? It must be conceded, 

 however, that the value of a farm supporting the proper growth of 

 trees is greater than that of a similar farm barren of tree growth. 



Certain slight disadvantages are incident to windbreak planting, but 

 they are negligible when compared to the advantages. The windbreak 

 must be located where it will furnish the maximum protection and it is 

 thus necessary to use soil areas which could be planted to crops. In 

 this connection the windbreak should be regarded as crop insurance and 

 in those sections where protection planting is necessary 10 per cent of 

 the farm area might well be devoted to windbreaks in view of the pro- 

 tection and increased crop returns secured on the remaining 90 per cent. 



As a result of shading, coupled with competition between the roots 

 of the trees and the crop plants for food and moisture, there is a loss 

 in yield on the strip of land immediately adjoining the windbreak. 

 This slight loss is more than offset by increased returns from the re- 

 mainder of the protected area. It can be further lessened by wise 

 selection of the trees, the direction of the windbreak itself and by 

 proper handling afterwards. Do not plant trees that have wide-spread- 

 ing crowns or rambling root systems. Cultivation conserves the avail- 

 able soil moisture and consequently restricts the spread of the roots in 

 their search for food. A ditch dug on the field side of the windbreak 

 a reasonable distance from the base of the trees will effectually stop the 

 spread of the roots in that direction. 



ARRANGEMENT AND LOCATION OF WINDBREAKS. 



Three types of windbreaks are generally recognized : single rows of 

 trees, belts composed of two or more rows and groves of trees in natural 



