11 



SHELTERBELTS AND WINDBREAKS. 



The terms " shelterbelt " and " windbreak " are often used inter- 

 changeably. When distinguished, shelterbelt is applied to trees 

 planted in groups of considerable size, while one or two rows to 

 check the wind is called a windbreak. Since this discussion applies 

 equally well to both shelter-belts and windbreaks, the latter term is 

 chosen for the sake of simplicity. 



In an open country of high winds, nothing adds more to the com- 

 fort of existence than a protecting belt of trees about the home. 

 Whether the wind be the hot one of summer or the snow-laden blast 

 of winter, its force is spent on the trees, and the house within is 

 not swept by every passing gust. Orchards need windbreaks to 

 save them from injury in the gales that accompany summer storms 

 as well as to protect them from ordinary winds throughout the 

 year. Gardens are more successful when surrounded by trees. Wind- 

 breaks benefit animals as much as their owners. 



Any species that is adapted to the region and suits the taste of 

 the planter may be used for a windbreak. Where they will succeed, 

 evergreens are desirable, since they afford better winter protection 

 than the deciduous species. The man who wants a windbreak, how- 

 ever, does not care to wait for slow-growing trees. The Austrian and 

 Scotch pines grow quite rapidly and serve the purpose well. A 

 windbreak consisting of a single row, to be effective, should be of 

 a densely growing type that branches close to the ground. For low 

 breaks of this character the Russian mulberry and Osage orange 

 are excellent. The tamarix, while more like a large shrub than a 

 tree, does well for low windbreaks around garden patches and similar 

 areas. It is easily propagated by cuttings, grows rapidly, and is 

 quite hardy. The cottonwood is the common tree used for wind- 

 breaks in the valleys. 



One of the most important functions of the windbreak is the saving 

 of soil moisture within the protected area. In the Monthly Weather 

 Review for September, 1888, were published the results of experiments 

 made by the United States Signal Service to determine the effect of 

 the rate of wind on evaporation from a "water surface. The experi- 

 ments were made with a Piche evaporometer, under constant condi- 

 tions of humidity and temperature. The figures obtained are given 

 in the following table, in which wind velocity is expressed in miles 

 per hour and the unit of evaporation is that in a calm : 



[Cir. 161.] 



