Scientists Propose Thinning Sierra Forests to Enhance Water Runoff
By James Leonard, UC Merced
Runoff from the Sierra Nevada, a critical source of California’s water supply, could be enhanced by thinning forests to historical conditions, according to a report from a team of scientists with the University of California, Merced, UC Berkeley and Environmental Defense.
The team proposes to test the hypothesis that forest-management strategies that use thinning to reduce fire risk and maintain the historical mix can also increase water yield and extend the snowpack in the Sierra Nevada.
Scientists believe thinning forests could enhance water runoff from the Sierra Nevada. They suggest that by selectively reducing the number of trees — which use large amounts of the water received through precipitation — the amount of water that is released from the forest as runoff could increase. This enhanced runoff could make things easier for farmers and water managers statewide.
As part of the Sierra Nevada Watershed Ecosystem Enhancement Project (SWEEP), the scientists plan to reduce forest density in test areas and examine the impacts on water runoff, forest health and other ecosystem services, and provide a template for broader forest management in the Sierra Nevada.