16 



lowing trees, when placed on hospitable soil fulfilling the require- 

 ments of each individual species, may, in the northern half of the 

 region, be successfully grown as windbreaks : 



Arborvitse. White elm. Laurel-leafed willow. 



Green ash. European larch. Russian golden willow. 



Boxelder. Russian wild olive. White willow. 



Cottonwood. Western yellow pine. 



Cork elm. Black Hills spruce. 



In the southern half of the Middle West, also the green ash, cotton- 

 wood, white elm, Russian wild olive, and western yellow pine may 

 be successfully grown, and in addition the following species : 



Chinese arborvitse. Honey locust. Osage orange. 



Wild China. Mesquite. Persimmon. 



Black locust. Russian mulberry. Shittimwood. 



These lists do not include all of the best timber trees that might be 

 grown in the Middle West, for many valuable timber trees will not 

 endure such severe exposure as a windbreak is subject to. 



In the establishment of a windbreak wisdom is required in the 

 placing of the different species. A windbreak composed of more 

 than one species is usually the most effective. An excellent method 

 of arrangement is to place the shortest trees in the outside row 

 (toward the- prevailing wind), to plant a somewhat taller species 

 next to them, and to place the tallest trees in a third row on the side 

 adjacent to the buildings or the area which is to be protected. This 

 causes the wind to strike the trees as it would strike the face of a 

 steep hill, deflecting its course upward. If the tallest trees of the 

 third row consist of a flexible species, such as cottonwood, European 

 larch, white willow, or honey locust, they will bend before the wind, 

 and act as a cushion to deflect it upw r ard and over the object to be 

 protected. A satisfactory windbreak 5 rods in width, for the pro- 

 tection of the north and west sides of a farmstead (see fig. 2) and 

 adapted to Minnesota and the Dakotas, is as follows: Plant 13 rows 

 of trees, parallel to one another and 6 feet 10 inches apart. The 

 first two rows on the north and west edges of the belts should consist 

 of Russian wild olive, the third and fourth rows of arborvitae, the 

 fifth and sixth rows of boxelder, the seventh and eighth rows of 

 white elm, the ninth and tenth rows of white willow, and the remain- 

 ing three rows of common cottonwood. Such a plantation, when 

 mature, will appear like a wall with a sloping top, the highest side 

 being where the cottonwoods are planted. 



Carrying out this same principle for Oklahoma and Texas, with a 

 change in the position of the plantations to afford protection from 

 southwest winds (see fig. 2), the following method is advised: The 



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