8 WINDBREAKS. 



barn prop, or a temporary substitute for a wagon tongue, but his 

 methods are wholly destructive, and the condition of the forest 

 plantation goes from bad to worse. The great need is for better 

 management; some care to secure natural reproduction to replace the 

 old trees; underplanting, if necessary, to fill out the stand and to 

 insure a continuous crop; and the exclusion of cattle from young 

 groves. In general, this care has not been given to forest plantations, 

 and, as a result, the revenue from them is only a fraction of what it 

 would be under good management. The Forest Service has already 

 issued a number of publications 1 which show that the revenue to be 

 derived from plantations of forest trees properly selected and managed 

 is considerable. The farmer's main* objection is that he can not 

 afford to wait for his income until the trees have matured. When the 

 protective value of timber tracts is rightly considered, however, as 

 will be shown in the following pages, there will be in the benefit to 

 crops, and in other helpful influences of the belt of trees, an annual 

 income of considerable magnitude in addition to the value of thin- 

 nings, which, in certain regions, will bring the productiveness of the 

 forest up to that attained by field crops. 



The very lack of reliable information concerning the protective 

 value of windbreaks, together with the now common argument that 

 they do more harm than good, makes their study exceedingly impor- 

 tant. The present study has been concerned entirely with the 

 collection of data showing the effects of windbreaks upon field crops 

 and with calculations of their net value to the average farm of the 

 Middle West. The economic importance of tree planting in this 

 region can be realized only when it is known that there are, for 

 example, in one township in Harvey County, Kans. (middle eastern), 

 approximately 170 miles of windbreak, mostly single rows of osage 

 orange, with an average height of about 20 feet. In a valley county 

 (Platte) of Nebraska there are in one township approximately 22 

 miles of rows, belts, and groves, mostly cottonwood, with an area of 

 about 425 acres and an average height of 55 feet. On the uplands in 

 the State (York County) there are in a single township about 40 

 miles of windbreaks. In Faribaitlt County, Minn., one township 

 contains approximately 400 acres of cottonwood and willow groves. 



The Forest Service has conducted experiments to obtain a clear 

 idea of the influences of windbreaks upon the atmospheric and soil 

 conditions which affect the growth of plants. These influences known, 

 it is but a step to apply these general principles to local conditions 

 and to determine the relative values of various species and of various 

 arrangements of windbreaks with respect to local winds, and their 

 positive value to certain crops. 



1 Miller: Forest Planting in Eastern Nebraska, Cir. 45; Forest Planting in the North Platte and South 

 Platte Valleys, Cir. 109. Kellogg: Forest Planting in Western Kansas, Cir. 161; Forest Planting in Illinois, 

 Cir. 81 Fetherholf : Forest Planting on the Northern Prairies, Cir. 145. Baker: Native and Planted Tim- 

 ber of Iowa, Cir. 154. 



