FORESTS IN THEIR RELATION TO RAINFALL. 233 



debris which, rapidly agglomerated, rush into the channel ; the 

 brooks called to replace the torrent receive only pure water ; flood 

 waters flowing off gradually and made harmless by the regulation 

 of the torrent bed and of the slopes." 



b. To conserve springs and to aid in the more even dis- 

 tribution of terrestrial waters. — These subjects are 

 intimately associated with the preceding, the necessity for 

 the tempering of the floods being only an extreme case of 

 the conservation and distribution of water. 



"Under the forest shade the soil is in a state of perpetual 

 increment from the humus afforded by decaying foliage and trunks 

 and roots hold it together ; the branches break the violence of the 

 rainfall; the spongy absorbent nature of the soil enables it to 

 retain it; and this, slowly sinking into the underlying rock, pre- 

 serves the needful moisture in the soil, and becomes the source of 

 perennial springs. But if such a mountain forest be suddenly 

 laid low, we have not only to fear the appearance of an under- 

 growth prejudicial to tree reproduction, but we have to fear the 

 total loss of the soil, which, exposed to the violence of the falling 

 rain, and no longer held together by the tree-roots, gets washed 

 down into the valley below, until the bared subsoil or rock is 

 unfitted for the support of any but the scantiest herbage." 1 



And again: — 



" It has been well established that forests have a most impor- 

 tant bearing upon the conservation of rainfall; that the forest 

 floor permits a seepage of water to the source of springs, and thus 

 maintains their steady flow; that they hold back the precipitation 

 that falls, especially in the form of snow, thus preventing or 

 ameliorating the effects of dangerous freshets. There is not the 

 slightest doubt of their great importance to the welfare of man, 

 but all these facts do not affect the question of their influence 

 upon precipitation." 2 



1 Amery, " Notes on Forestry," page 12. 



2 H. A. Hazen, op. cit. 



