THIRD ANNUAL YEAR BOOK— PART X. 623 



EVERGREENS FOR WINDBREAKS. 



A. T. Irwin, Ames, Iowa. 



The planting of evergreens, like other enterprises, is likely to be 

 viewed in its pioneer stages primarily from the material rather than from 

 the esthetic. The most impotant subject under the former heading is 

 the one of planting for shelter belts, etc. In evergreen planting, as in 

 other operations of the early settler, immediate results are of prime con- 

 sideration, hence even in evergreen planting we have what may be termed 

 the "popular stage" of development; that is, the use of evergreens which 

 are hardy and effective but above all, of rapid growth, something that 

 will give early returns. Probably the trees which fulfill these requirements 

 best are the Scotch pine and Norway spruce. This, no doubt, accounts 

 for their extensive use throughout the northwest, and for this purpose 

 they have answered admirably. It should be remembered, however, that 

 these evergreens as with other rapid growing trees such as the cotton- 

 woods, soft maples, etc., the wood is not durable, and early results are 

 always obtained at the exnense of longevity. 



In Iowa we are now past the pioneer stage and the point I desire to 

 emphasize is that with this new era of permanent improvement and bet- 

 ter buildings, better fences, better homes, we should also make it a point 

 to plant species of evergreens which are longer lived and more enduring. 

 As a good example of this class we may mention the Austrian pine. Though 

 of slower growth than the Scotch, the indications are that its life period 

 is fully double that of the latter. On the Iowa State college campus are 

 to be found many species of the Scotch and Austrian pines which were 

 planted in the early seventies. Each summer for the past four or five 

 years we have been compelled to remove a number of specimens of the 

 Scotch and the remaining ones give evidence of decay. The Austrian, how- 

 ever, with few exceptions, are thrifty and yet in their prime. 



Among our native pines of this long lived class we would name the 

 bull pins (Pinus ponderosa, variety scopulorum) . From the limited plant- 

 ing so far many of the species give good evidence of being a strong, hardy, 

 long lived tree, and adapted even where the climatic conditions are severe. 

 Its scarcity in the nursery probably precludes its more extensive use at 

 present. 



A third species, and a monarch of them all in some respects, is the 

 white pine. It is somewhat exacting and requires a soil which is neither 

 too dry nor too wet. In severe locations it sometimes proves tender in 

 the first three or four years of its growth. For the first ten years after 

 planting its growth is slow, but after this age the annual growth is very 

 heavy and the tree is also more hardy. To secure protection for the first 

 few years, and also to combine early results with permanency, windbreaks 

 of the Scotch pine and the White or with some of the other species named, 

 make an ideal combination. In many sections of our state the belts of 

 Scotch pine have reached their maturity, and in renewing them let us not 

 fail to build a more permanent and enduring foundation. 



