Upon the prairies the winds are almost as constant and regular 

 as they are upon the sea. In the spring they blow from the southeast 

 and bring the rains upon which agriculture largely depends. In the 

 summer the prevailing winds are from the south. These, accom- 

 panied by clear skies and continual sunshine, have a wonderful power 

 of drawing moisture from the soil. The effect of this proves serious 

 when these winds are supplanted by the hot winds from the plains. 

 Many a Carolina poplar tree records the occurrence of such winds 

 in a blazelike blight on the southwest side, whence these winds blow. 

 In winter the prevailing winds are from the north and west. The 

 air is then clear, dry, and bracing. Occasionally these winds are 

 very cold, blow with great velocity, and, when accompanied by snow, 

 become the dreaded blizzard. 



EARLY PLANTING. 



On the unsettled prairies there were no barriers to obstruct the 

 constant winds. Tree planting was early recognized as the best 

 means of accomplishing this. In order to encourage tree planting 

 generally, Congress passed the timber culture act of March 3, 1873. 

 Under this law and its later modifications a good deal of planting 

 was done, both to meet the requirements of the act and to secure the 

 benefit of protection. 



In the matter of growing trees some had better success than others. 

 Europeans often used to good advantage the experience they had got 

 abroad. A number of species were introduced; but generally the 

 native trees furnished the most readily available planting material. 

 Cottonwood, boxelder, silver maple, green ash, and white elm are the 

 species that have been most generally tried. Partial successes are 

 rather more common than complete successes. Failures may be attrib- 

 uted in some cases to insufficient preparation of the soil, to wide 

 spacing of the trees, infrequent cultivation, to insects, fire, animals, 

 etc., but mostly to the occasional droughts already referred to. Fail- 

 ures of conifers result from the planting in too small quantity, from 

 the use of too large plants, and from the drying of the roots before 

 planting. Yet, notwithstanding failures, there are many good 

 groves. 



In the native trees the discussions of the merits of the species are 

 based upon the general conditions of the region and upon actual 

 measurements of a number of typical planted groves. In the case of 

 introduced trees the data are derived from measurements of groves 

 and from literature on the requirements of these trees. Adaptability 

 and economic usefulness have been the leading considerations in 

 recommending a species for future planting. 



[Cir. 145] 



