82 



WINDBREAKS. 



Nebraska, Iowa, and Minnesota is the white willow (Salix alba Linn) 

 of Europe. This is very short-lived and attains its greatest annual 

 value at the end of 10 years. Because of its early rapid growth it must 

 be considered a useful tree. It makes severe drains on soil moisture, 

 and as its roots are almost wholly laterals and close to the surface, it 

 does considerable damage along the edges of fields. On this account 

 farmers in Iowa and Minnesota have to a large extent removed the 

 rows of willows which formerly surrounded their fields. 



In Tables 20 and 21 the area charged to single rows of willow has 

 been calculated on the basis of the damage to a crop of oats in the 

 season of 1908. The damage was apparent out to about twice the 

 tree height, and amounted on either side of the north-south windbreak 

 to the complete loss of grain in a strip almost exactly as wide as the 

 height of the trees. 



TABLE 20. White willow estimates posts. 

 (All on quality A situations.) 



Three rows, 14 feet apart. 2 Four rows, 15 feet apart. 



TABLE 21. White willow estimates fuel. 





