Forestry in Minnesota
Format: Paperback
ISBN13: 9780217725361
Paperback|9780217725361
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III. FOREST INFLUENCES. Upon careful observation it will be found that a single larfe spreading tree growing in an open field appreciably affects climatic and soil conditions in the following ways: (i.) During the day the ground under a tree is protected from the sun's rays and is therefore cooler than soil not protected. As a result of this protection, the air under the tree is cooler than the air in the open, and, as it is constantly in circulation, tends to cool the air in the immediate vicinity of the tree on sunny days. (2.) At night a tree retards the radiation of heat from the ground under it. This tends to equalize the temperature of not only the soil and air under the tree, but that in the near vicinity. Therefore, though a tree may reduce the temperature of the soil and air on sunny days or during a short period of warm weather, it may, on the other hand, increase the temperature at night or during a short period of cool weather. For example it may be noticed that vegetables growing near trees are frequently uninjured by autumn frosts which destroy those growing in the open. (3.) A tree aids in retaining water in the surface soil to the leeward by breaking the force of the wind, and thus retarding evaporation, for it is known that evaporation increases with the rapidity of the air currents. It retains the water in the surface soil under the tree by shading the soil and thus retarding evaporation. The large amount of water which is transpired by a tree is largely drawn from the subsoil, and this increases the humidity of the surrounding air without drawing on the water of the surface soil. But some kinds of trees take up so much of the water from the soil as to preclude the growing of crops in such places near them. (4.) The leaves that fall to t...
| ISBN-13 | 9780217725361 |
|---|---|
| ISBN-10 | 0217725368 |
| Weight | 0.89 Pounds |
| Dimensions | 9.00 x 6.00 x 0.61 In |
| List Price | $19.66 |
| Format | Paperback |
|---|---|
| Pages | 272 pages |
| Publisher | |
| Published On | 2009-08-01 |
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