. Bulletin. Forests and forestry -- United States. 38 A PRIMER OF FORESTRY. may not flud the right surroundings for successful ger- mination, or the infant trees may perish for want of water, light, or suitable soil. Where there is a thick layer of dry leaves or needles on the ground, seedlings often i^erish in great numbers because their delicate rootlets can not reach the fertile soil beneath. The same thing happens when there is no humus at all and the surface is hard and drj^ The weight of the seed also has a powerful influence on the character of repro- duction. Trees with heavy seeds, li
. Bulletin. Forests and forestry -- United States. 38 A PRIMER OF FORESTRY. may not flud the right surroundings for successful ger- mination, or the infant trees may perish for want of water, light, or suitable soil. Where there is a thick layer of dry leaves or needles on the ground, seedlings often i^erish in great numbers because their delicate rootlets can not reach the fertile soil beneath. The same thing happens when there is no humus at all and the surface is hard and drj^ The weight of the seed also has a powerful influence on the character of repro- duction. Trees with heavy seeds, like Oaks, Hickories, and Chestnuts, can sow them only in their own neighbor- hood, except when they stand on steep hillsides or on the banks of streams, or when birds and squirrels carry the nuts and acorns to a distance. (See PI. XYIII.) Trees with light, winged seeds, like the Poplars, Birches, and Pines, have a great advantage over the others, be- cause they can drop their seeds a long way oft'. (See figs. 31, 32.) The wind is the means by which this is brought about, and the adaptation of the seeds them- selves is often very curious and interesting. The wing of a Pine seed, for example, is so placed that the seed whirls when it falls, in such a way that it falls very slowly. Thus the wind has time to carry it away before it can reach the ground. In heavy winds Pine and other. Fig. 36.—Mixed forest of Wbite Pine, Chestnut, and Oak at Milford, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Division of Forestry. Washington : G. P. O.
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