PART II 



FORESTRY AND CONSERVATION. 



INTRODUCTION. 



Forestry is the preservation of the forests by wise use, in its 

 broadest sense. Preservation by wise use not only means the eco- 

 nomic handling of the natural forests, but also the commercial and 

 economical planting of forest trees in places now barren. In many 

 ways it is the most vital problem in the United States, directly as 

 well as indirectly, to the farmer as well as the lumberman. By 

 saving the forests the prosperity of each individual and of the na- 

 tion is increased and preserved. The primary object of the forest 

 policy of the United States is the making and preserving of pros- 

 perous homes upon which rest the foundations of our Government. 

 (Theodore Roosevelt F, S. Cir. 25.) 



INFLUENCE OF FORESTS ON AGRICULTURE. 



The Forest Waters the Farm. Whether forests increase the 

 amount of precipitation within or near their limits is still an open 

 question, although there are indications that under certain condi- 

 tions large, dense forest areas may have such an effect. At any 

 rate, the water transpired by the foliage is certain, in some degree, 

 to increase the relative liumidity near the forest, and thereby in- 

 crease directly or indirectly the water supplies in its neighborhood. 

 This much we can assert, also, that while extended plains and fields, 

 heated by the sun, and hence giving rise to warm currents of air, 

 have the tendency to prevent consideration of the passing moisture- 

 bearing currents, forest areas, with their cooler, moister air strata, 

 do not have such a tendency, and local showers may therefore be- 

 come more frequent in their neighborhood. But, though no in- 

 crease in the amount of rainfall may be secured by forest areas, the 

 availability of whatever falls is increased for the locality by a well- 

 kept and properly located forest growth. The foliage, twigs, and 

 branches break the fall of the raindrops, and so does the litter of 

 the forest floor, hence the soil under this cover is not compacted as 

 in the open field, but kept loose and granular, so that the water can 

 readily penetrate and percolate; the water thus reaches the ground 

 more slowly, dripping gradually from the leaves, branches, and 

 trunks, and allowing more time for it to sink into the soil. This 

 percolation is also made easier by the channels along the many 

 roots. Similarly, on account of the open structure of the soil and 

 the slower melting of the snow under a forest cover in spring, where 

 it lies a fortnight to a month longer than in exposed positions and 

 melts with less waste from evaporation, the snow waters more 



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