. Bulletin. Forests and forestry -- United States. 46 A PRIMER OF FORESTRY. water enough for all the trees, aud often more than enougL, as for example in the Adirondack forest. The struggle for space and light is thus more important than the struggle for water, and as it takes place above ground it is also much more easily observed and stud- ied. (See fig. 42 and PI. XXY.) Light and space are of such imi:>ortance because, as we have seen, the leaves can not assimilate or di- gest food except in the l^resence of light and air. The rate at which a tree can grow and make new wood is decided ch
. Bulletin. Forests and forestry -- United States. 46 A PRIMER OF FORESTRY. water enough for all the trees, aud often more than enougL, as for example in the Adirondack forest. The struggle for space and light is thus more important than the struggle for water, and as it takes place above ground it is also much more easily observed and stud- ied. (See fig. 42 and PI. XXY.) Light and space are of such imi:>ortance because, as we have seen, the leaves can not assimilate or di- gest food except in the l^resence of light and air. The rate at which a tree can grow and make new wood is decided chietiy by its ability to assimilate and digest plant food. This power depends upon the number, size, and health of the leaves, and these in turn upon the amount of space and light which the tree can secure. THE LIFE OF A FOREST Fig. 42—On the edge of a very dense forest. The leaning trees are dead, killed by the crowding aud shade of their stronger neighbors. Spruce in the White Mountains, New Hamp- shire. The story of the life of a forest crop is then largely an account of the com- petition of the trees for light and room, ixnd, although the very strength which enables them to carry on the fight is a result of their association, still the deadly struggle, in which the victims are many times more in number than those which survive, is apt alone to absorb the attention. Yet the mutual help of the trees to each other is always going quietly 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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