Page:Popular Science Monthly Volume 21.djvu/15

Rh of the ultimate and full-grown forest, the final outcome of their one hundred and twenty or one hundred and sixty years of watching and culture. If, for instance, they propose to raise what shall be at last a forest of oak-timber, they will plant with the oaks successive rows of the pine, the beech, the maple, the larch, or the birch, each at a distance perhaps of twenty feet from its own kind, but each only four feet from some neighbor. After a few years the quickest-growing trees will be removed—those nearest the oaks—and this will go on from time to time till, finally, the oaks are left to develop themselves to their fullest stature and their greatest strength. As a rule, the thinning is made at such intervals that half the trees originally planted will be removed by the time they are twenty feet high. The number on an acre should not exceed eight hundred when they have reached the height of thirty feet, and when forty feet high only three hundred or three hundred and fifty should remain. These successive thinnings, it is estimated, will more than pay for the care and labor, as well as interest on the land, leaving the final forest as clear profit. And it is to be considered that very much more valuable timber is produced on an acre of ground with this careful and systematic treatment than when a forest is left to grow up by chance and in neglect, as is so commonly the case. There is as great difference in the returns, proportionally, as there is between the yield of a vegetable-garden carefully tended and that of one left without proper cultivation and allowed to be overgrown with weeds. Dr. Berenger, head of the School of Forestry at Vallambrosa, Italy, says that "while an uncultivated woodland, taken for a long period, and counting interest and taxes, would yield almost nothing to the capital invested, it is well established that the same land, managed according to modern science, would, in the long run, yield a revenue both conspicuous and constant."

In many parts of our country, on the plains and prairies especially, and wherever tree-planting is undertaken, except for utilizing waste or rough and comparatively inaccessible ground, which would not be profitable for ordinary tillage, the most desirable mode of planting will be in belts or borders rather than in blocks. These belts should be so disposed as to serve as screens from the strongest and most hurtful winds. There can thus be secured an equally abundant growth of timber, while the screen it furnishes will greatly increase the product of other crops, and serve to promote the comfort of all, whether man or beast, who can have its shelter. The variety of products on a farm may be thus greatly increased also. Tender vegetables and fruit-trees readily flourish under the protection of such shelter belts of forest-trees which could not otherwise be cultivated with success, if at all. And the protection of such belts extends farther than many suppose. It is estimated that their beneficial influence reaches, in horizontal distance, about sixteen times their height. It is probable, therefore, that belts of trees might be so disposed, on almost any farm, that the