ELEMENTS OF CONSERVATION. 33 



the forest. The only other conservative effect of forests on 

 water supplies is their effect in retarding: the melting of the 

 snows. This acts as an important function in the prevention 

 of freshets by giving the snow a longer time to melt so that 

 the snow water has a better chance to sink into the ground. 

 It is of course more evident in evergreen than in deciduous 

 forests. On the grounds of the MinnesotaExperiment Station 

 where the woodland consists of a low growth of Oak, the snow 

 is often retained in the woods a week longer than in the open. 

 This often allows the snow water fr6m the fields to almost 

 wholly run off before it has begun to flow from the woods. 

 Then again the daily flow of snow water from the woods is 

 much shorter than from the open fields during spring weather 

 when we have warm days and cold nights, for it begins later 

 in the morning and stops earlier in the afternoon. Under the 

 dense shade and mulch of the cedar swamps of Northern Min- 

 nesota the snow and ice often remain until the beginning of 

 summer. The Indians claim there has never been a time when 

 they could not find ice for their sick in the cedar swamps of 

 that section. This retarding effect on the melting of snows in 

 the spring and in preventing the run-off is of far greater im- 

 portance in the case of streams that rise in the high moun- 

 tains than in Minnesota and Wisconsin, where the land is 

 more nearly level. Where streams have their sources in 

 mountains, as those of Colorado and other Rocky Mountain 

 States, the cutting away of the forests causes a heavy flow of 

 water early in the spring and little water in the summer when 

 it is most needed for irrigation purposes. This has become 

 so evident that the Chamber of Commerce of Denver, Colora- 

 do, recently petitioned the President of the United States to 

 reserve such land in forests and administer it at public 

 expense, and in their petition used In part the following 

 language: 



"The streams upon which the irrigation system of Colo- 

 rado depend are fed by the springs, rivulets, and melting 

 snows of the mountains, which in turn are nourished and pro- 

 tected by the native forests. Where the forests have been 

 destroyed and the mountain slopes laid bare most unfavorable 

 conditions prevail. The springs and the rivulets have 

 disappeared, the winter snow melts prematurely, and the flow 



