RESULTS OF MEASUREMENTS. 



37 



A case measured in Edwards County, Kans., shows that while 

 sapping by forest trees may be appreciable, it need not, in a young 

 orchard, result in any damage to the fruit trees. The windbreak 

 consisted of two rows of cottonwood 15 feet high and 10 feet apart. 

 Ten feet to the north was a row of 22 peach trees and 15 feet farther 

 was a second row containing the same number of trees. The results 

 of tree and soil measurements are shown in Table 8. 



TABLE 8. Relation of orchard and forest trees. 



Although moisture was not abundant and the cottonwoods had 

 to some extent robbed the first row of fruit trees, the shading effect 

 was not felt and no damage had so far resulted. Instead, the trees 

 nearest the windbreak seemed to be doing better than those in the 

 second row. 



Grainfields. In grainfields the effect of sapping is shown by the 

 smaller size of the plants and smaller heads of grain. Even if there 

 is abundant moisture when the plants are young, and they attain 

 good size, a late drought will parch them badly. The fields first 

 become " burned " or " fired" along the edges where there are trees 

 or heavy sod. With small grains the result is usually the premature 

 ripening of the heads and loss of the grain by shelling out. With 

 corn, the ears are reduced in size and the kernels do not fill out. 

 In an instance examined in the fall of 1908, immediately after the 

 first frost, it was shown that the effect of the tree roots (green ash) 

 had been to cause the earlier ripening of the corn, especially that 

 growing near the tips of the roots. The advanced ripening was 

 evident not only in the kernels of corn but also in the plant. 



With one or two exceptions, the effect of sapping was not apparent 

 in corn yields, which increased very steadily once the limit of the 

 shaded zone had been reached. In the exceptional cases there is a 

 sudden checking of the rise of the yield curve, indicating the zone of 

 activity of the tree roots. With oats and wheat, however, the 

 influence of tree roots was much more apparent in all cases (see 

 diagrams 7 to 13). Both of these small grains suffered from lack of 

 moisture early in the spring before corn had been planted. In a field 

 of wheat north of a grove of soft maple (see diagram 14) the grain was 

 notably poor for about 45 feet from the trees, which were 29 feet high. 



