Forestry and Government 169 



writings of the early travellers. Much more con- 

 spicuous than in the floods of the great rivers is the 

 influence of forest disappearance on the dwindling 

 of small rivers and brooks, and the occasional dry- 

 ing up of springs. This process is quite noticeable 

 in all regions that have been settled within the last 

 fifty years ; but it is by no means certain that the 

 phenomenon is caused exclusively by the removal 

 of forests. 



The greater instability in the water stages of 

 rivers, the more destructive freshets and protracted 

 low water, which are characteristic of streams in a 

 district with little or no forest cover, are, of course, 

 injurious in many ways. But the greatest damage 

 caused by them is that of over-erosion. A stream 

 running rapidly at high water is a far more effective 

 agent than a moderate stage of water in tearing 

 away soil and carrying it down to be deposited 

 where it may not be wanted. What is true of the 

 river is true of the smallest rill. The danger of such 

 excessive erosion is but small on plains or districts 

 with slightly rolling topography. But. among the 

 hills and mountains it becomes very great. Where 

 a forest covers the steep sides of a hill the rush of 

 water into the valley is very much retarded, but on 

 an open slope it can act tvith full force, as may be 

 seen at every such hillside, where the rain-water is 

 gradually wearing ravines into the surface. Where 

 the mountains are deprived of a considerable por- 

 tion of their forests, the streams occupying their 

 valleys are sure to receive a much greater amount 



