SIZE OF EFFICIENT WINDBREAKS. 97 



(6) On the uplands and poorer situations of the Middle West, two 

 classes of windbreaks are recommended; they may well be used on 

 different parts of the same farm. The osage-orange hedge will serve 

 in the driest situations, because of its drought resistance. Its sphere 

 of influence can not be very wide; nevertheless, it will probably be 

 inadvisable to have these windbreaks at more frequent intervals 

 than 40 rods. Four osage-orange hedges, 25 feet high, will greatly 

 reduce the general wind velocities on a quarter section and will give 

 efficient protection to a large proportion of it. The windbreaks 

 should, of course, extend from east to west across the farm. The 

 post material should be cut before the end of 25 years, except on 

 very dry situations, where it will require more time to grow first-class 

 posts. It will be preferable to remove the larger trees from time to 

 time rather than to destroy the hedge. If the hedges are to be cut 

 to the ground, only one of the three or four on a farm should be 

 taken in a single year. 



While the osage hedge will furnish all of the posts needed, it will 

 be best in most cases to have one wide belt of trees more nearly of a 

 forest character. Green ash, honey locust, and Scotch and Austrian 

 pines will produce a much larger volume of wood than can be 

 obtained from osage orange. On situations not too dry, honey 

 locust may profitably be planted in belts 44 feet wide if retained to 

 the age of 30 years. Green ash has about the same capacity for height 

 growth and furnishes more protection. Neither of these species 

 alone makes an efficient windbreak; they should be supplemented 

 with conifers. About eight rows of these hardwoods, 4 feet apart, 

 should be planted at the outset, to be supplemented in a few years 

 with three rows of Austrian pine on the north side. Scotch pine 

 grows equally well, but on medium situations where severely exposed 

 it will not make good form and will be fit only for fuel. 



A belt of this sort should be so located as to protect the house, barn, 

 and orchard from north winds. Because of its narrowness, all of the 

 snow which it checks will not be deposited within the belt, so it should 

 not be located too close to the north side of buildings or roads. 



2. THE NORTHERN PRAIRIES. 



(a) Primarily, in all of the northern prairie region the protection 

 is needed against cold and dry winter winds and, secondarily, against 

 the occasionally dry westerly winds of summer. The warm chhiook, 

 occurring in early spring, may also have very damaging consequences. 

 To meet all of these, windbreaks of both orientations must be used, with 

 about two of the north-south to one east- west. On good situations 

 many conifers will succeed, about the most desirable being, in the 

 order of their desirability, Scotch pine, red or Norway pine, Colorado 

 blue spruce, and Black Hills spruce. Scotch pine develops well only 

 when planted closely. 



92290 Bull. 8611 7 



