Page:Popular Science Monthly Volume 81.djvu/538

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532
THE POPULAR SCIENCE MONTHLY

PSM V81 D538 A natural forest of white pine in minnesota.png

A Natural Forest of White Pine in Minnesota.

mill, we could every year cut the more mature trees, leave the younger ones to grow, and in reasonable time bring it into a normal forest. Usually, however, natural forests are remote from established lines of transportation, and the lumberman who handles them must construct temporary logging railroads which are taken up when the timber has all been cut. He has invested his money, expecting to get it back soon with a profit and can not wait for trees to grow. He usually cuts clean as he goes. He can not afford to practise forestry and no reasonable person expects him to do so. It would take too long for nature unaided to renew forest. Natural reforestation has as good a chance in Germany as anywhere because fire there does little damage. But Germany plants over a hundred thousand acres of forest annually.

If we were to start an artificial pine forest it would be by planting seedlings—nursery grown trees—two years old, four feet apart, requiring at that rate 2,722 seedlings per acre. If land we purpose using happens to be part of an abandoned farm or is land from which natural forest was cut twenty or thirty years ago, probably five per cent, of the area is already well stocked by nature with valuable kinds of timber trees. Probably another five per cent, of the area consists of rocks or wet places that can not be planted, so that only ninety per cent, of our area will require to be planted.

Why should trees be planted as close as four feet? To get the ground shaded as soon as possible, to promote moisture and fertility; also to promote height growth. In a crowded forest the shade causes the trees to shed their lower limbs. It is only in this way that long smooth logs, free from knots, are produced. Every one has seen that a tree in the open grows too many branches to make good timber. In a