. Bulletin. Forests and forestry -- United States. BEGINNING OF THE STRUGGLE. 53 ill height and spread of crown. Growth in this way was going on unchecked among the young trees be- fore the crowns met, but now only the upward-grow- ing branches can develop freely. The leaves at the ends of the side branches have now less room and, above all, less light, for they are crowded and thrust aside by those of the other trees. Very often they are bruised by thrashing against their neighbors when the wind blows, or even broken off while still in the bud. Leaves exposed to such dangers are un- healthy.
. Bulletin. Forests and forestry -- United States. BEGINNING OF THE STRUGGLE. 53 ill height and spread of crown. Growth in this way was going on unchecked among the young trees be- fore the crowns met, but now only the upward-grow- ing branches can develop freely. The leaves at the ends of the side branches have now less room and, above all, less light, for they are crowded and thrust aside by those of the other trees. Very often they are bruised by thrashing against their neighbors when the wind blows, or even broken off while still in the bud. Leaves exposed to such dangers are un- healthy. They tran- spire less than the healthy, undisturbed leaves of the upper part of the crown, and more and more of the undigested food from the roots goes to the stronger leaves at the top as the assimilating power of the side leaves dwindles with the loss of light. The young branches share the fortunes of their leaves and are vigor- ous or sickly according to the condition of the latter. For this reason the growth of the tops increases, while that of the lower lateral branches, as the tops cover them with a deeper and deeper shade, becomes less and less. Gradu- ally it ceases altogether, and the branches perish. This. Fm. 50.—Small saijlings of White Pine grow- ing thickly together. Milford, Pa. The space betsveeu each cluster or whorl of side branches marks one year's growth. These young Pines are beginning to grow rapidly in height because they can no longer spread at the 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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