Changes in storm flow as a result of forest clearing by cutting of trees and subsequent applications of herbicides were determined for a small mountainous watershed in New Hampshire by using a paired watershed as a control. Reduction of transpiration and interception losses produced wetter soils with less opportunity for storing rainfall. Consequently, quick flow volumes and instantaneous peaks were nearly always increased during the growing season. The absence of the hardwood forest canopy also caused earlier and more rapid snowmelt and affected most spring storm flow events involving snow water. In contrast, storm events occurring after soil moisture recharge in the fall and before the start of spring snowmelt were unaffected by forest clearing. Although the spring and summer storm flow changes were readily detectable, their magnitude was not great. The maximum increase in individual quick flow was 30 mm for the summer streamflow season and just over 50 mm during spring snowmelt. Mean quick flow changes were much lower. The relatively small amount of forest clearing currently taking place in New England headwaters should not increase downstream flood potential.
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