94 WINDBREAKS. 



Throughout a region, as in all the northern and western parts of the 

 United States, where drying winds are prevalent, where atmospheric 

 moisture is not superabundant, and where the danger from cold 

 storms at the critical time of year is great, it is safe to say that the 

 benefit to be derived from windbreaks of forest trees planted about 

 orchards will at all times far exceed the possible damage from " still " 

 frosts, from fungi, from insects, and from the dwarfing of trees on 

 the edge of the orchard. The storm of 1908 was typical of the storms 

 which occur in some portion of the northern United States nearly 

 every spring. It must be remembered, also, that even when the 

 storm consists of only a dry wind, the tender leaves and flowers may 

 be injuriously cooled by evaporation or blighted by drying out. 



WINDBREAKS FOB VARIOUS REGIONS. 



Windbreaks may profitably be used in six principal regions of the 

 United States. It is important to know what is the ideal windbreak 

 and what methods are necessary to obtain and maintain it in each of 

 these regions: 



(1) The Middle West, including southeastern South Dakota, west- 

 ern Iowa, Nebraska, Kansas, and eastern Colorado. 



(2) The Northern Prairies, including eastern Montana, the Dako- 

 tas, and southern Minnesota. 



(3) The Lake States, including also southeastern Minnesota and 

 northeastern Iowa. 



(4) The Eastern States, north of the thirty-ninth parallel. 



(5) The Southwestern States, including southwestern Kansas^ 

 western Oklahoma and Texas, Arizona and New Mexico. 



(6) The fruit-growing regions of the Pacific Coast States. 



1. THE MIDDLE WEST. 



(a) Cottonwood is the tree best suited for windbreaks in the 

 Middle West when these are planted on good, moist situations, on 

 river bottoms, or, in the extreme eastern part of the region, on rolling 

 uplands. The trees should be planted in belts from 125 to 150 feet 

 wide, running east and west, and should not be cut until about 45 

 years old, when their height will be approximately 90 feet. If 

 practicable, not all of the grove should be planted at the same time, 

 but a narrow strip which will form the center of the final belt should 

 first be set out, and the belt widened as the first planted trees become 

 taller. The range of ages should not be more than 10 years, and 

 the youngest trees should be on the outside, where their effects on 

 crops will be least deleterious. 



In a windbreak of cottonwood in which the trees are approxi- 

 mately the same age, underplanting with a tolerant hardwood or 



