464 DISCUSSION : FORESTS, RESERVOIRS, AND STREAM FLOW 
Mr. Pinchot. forest as it does in the open, the discharge of water would be greater, 
considering the whole water-shed, and floods would thereby be 
intensified. 
The only condition under which the melting, for like conditions, is 
anything like as fast as in the open is during a warm rain, such as 
often accompanies the “chinook” winds in the western part of the 
United States. When this happens, the effect is the same on the snow- 
drift in the gulch and on the snow blanket in the forest. It melts at a 
most rapid rate. Once melted, there is this difference: Water from the 
snowdrift is at once in the channel ready to swell the floods, while 
water from the snow blanket is caught up in the layer of leaves and 
humus overlying a porous soil, and is retarded at every moment in its 
downhill course. A portion seeps down through the humus into the 
stream, a large or even larger part goes into the earth and does not 
reappear for weeks or months. 
The assumption that, “of an 18-in. fall (of snow), perhaps 12 in. 
is on the trees and the rest spread evenly on the ground,’ is one 
which will be disputed at once by anyone who has made a habit of 
frequenting and observing the forests in winter. Such heavy retention 
of snow is seldom seen elsewhere as may be found in the cedar forests 
and swamps of the Northeast; yet even there the speaker, in some 
considerable experience, has never seen a condition which began to 
approach the proportion of two-thirds of the snow on the branches 
and one-third on the ground. 
The foregoing is but a partial statement of the relations of the 
forest to snow. Unfortunately, time is lacking to elaborate it. 
Turning to the influence of forests in preventing erosion, Colonel 
Chittenden says that “he has still to see a single example where the 
mere cutting off of forest trees has led to an extensive erosion 
of the soil.” He further says that “a soil that will sustain a heavy 
forest growth will immediately put forth, when the forest is cut down 
(or even burned down), a new growth, generally in part different from 
the first, but forming an equally effective cover to the soil.” 
Those who have studied the forests know that the value of young 
growth, so far as water supply is concerned, is vastly less than that 
of the old first growth. If Colonel Chittenden had followed the 
literature of forestry somewhat further, he would have learned that 
the destruction of the old forest immediately has the effect of dissipat- 
ing the humus which is the accumulation of tens and sometimes of 
hundreds of years. He would have learned, further, that the removal 
of old trees, however effected, reduces the value of the forest floor in 
promoting the permeability of the soil. 'There are endless illustra- 
tions which might be used, as in the Adirondacks, in Maine, and in 
California, where the type of growth which follows the destruction of 
the old forest is far less favorable to absorption than that which has 
been destroyed. 
