RESULTS OF MEASUREMENTS. 



67 



In only one case was there measureable benefit to corn crops on 

 the east side of north-south windbreaks, and in this case it was 

 offset by the damage from shading. No measureable benefit was 

 noted on the west side of windbreaks. These results were to be 

 expected since the measurements were taken in a region where there 

 is very little wind from either the east or the west. Southwest 

 winds may, to some extent, test the usefulness of the north-south 

 windbreak, but the east winds nearly always occur in cool and 

 cloudy weather. 



While the increase of both the weight and size of the ears is marked 

 (see PL XV, fig. 1), it is the increased height and luxuriance of the 

 vegetative growth which at once attracts attention (see PL XV, 

 fig. 2). As has been said, seed production can not be very greatly 

 increased by improvement of atmospheric conditions alone; the es- 

 sential chemical elements must be abundantly present in the soil. 

 Fodder production, however, is more dependent upon moisture, 

 light, and heat, and the influences of the windbreak greatly increase 

 the amount of fodder in a field. Fodder is not considered a valua- 

 ble asset in the Western States, where hay is plentiful, but there 

 are many regions in which it is closely utilized. Table 14 shows the 

 amount and percentage of fodder and grain increase at various points 

 in a cornfield north of a tall cottonwood grove. At the point of 

 greatest growth the increase in fodder and stalk amounts to 95.2 

 per cent of the normal, while the increase in grain amounts to 37.8 

 per cent. 



TABLE 14. Proportionate increase in fodder and grain due to windbreak influence in 



heating air and soil. 



Wheat and other early grains, because of their smaller heat require- 

 ments, do not respond so readily to these more favorable " hothouse" 

 conditions. 



Orchards may be affected both favorably and unfavorably by the 

 increased temperatures due to windbreaks. The rapid ripening of 

 the fruit and of the wood of the trees in late summer is just about 

 offset by the danger of accelerating the growth of buds and the 

 blossoms in spring. On the other hand, where warm spring winds, 

 like the Chinook, or where breezes from bodies of water are involved, 

 the effect of the windbreak will be beneficial in spring by preventing 

 this warm air from striking the trees. 



