. Bulletin. Forests and forestry -- United States. 52 A PRIMER OF FORESTRY. more or less exx^osed to the sun and wind, and so has become dryer and less fertile than if it had been under cover, and consequently the growth has been slow. But now that the crowns are meeting, the situa- tion becomes wonderfully changed. The soil begins to improve rapidly, because it is protected by the cover of the meeting crowns and enriched by the leaves and twigs which fall from them. (See figs. 48, 49.) THE BEGINNING OF THE STRUGGLE. In SO far the condi- tions of life are better, and in consequence the growth,
. Bulletin. Forests and forestry -- United States. 52 A PRIMER OF FORESTRY. more or less exx^osed to the sun and wind, and so has become dryer and less fertile than if it had been under cover, and consequently the growth has been slow. But now that the crowns are meeting, the situa- tion becomes wonderfully changed. The soil begins to improve rapidly, because it is protected by the cover of the meeting crowns and enriched by the leaves and twigs which fall from them. (See figs. 48, 49.) THE BEGINNING OF THE STRUGGLE. In SO far the condi- tions of life are better, and in consequence the growth, and more espe- cially the height growth, begins to show a marked increase. (See fig. 50.) On the other hand, all the new strength is in im- mediate demand. With the added vigor which the trees are now helping each other to attain comes the most urgent need for rapid development, for the decisive struggle is at hand. The roots of the young trees contend with each other in the soil for moisture and the plant food which it contains, while in the air the crowns struggle for space and light. The latter is by far the more im- portant battle. The victors in it overcome by greater rapidity of growth at the ends of the branches, for it is bj^ growth there, and there only, that trees increase. Fig. 49.—Group of White Pines (small saplings) in an opening among older trees. Milford, Pa. The lower branches are crowding each other vigorously, and will soon begin to 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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