Thursday, December 15, 2011
Global Forests Are Overlooked as Water Suppliers
The forests of the world supply a significant amount of moisture that creates rain. A new study published in Global Change Biology reveals how this important contribution of forests to the hydrologic cycle is often overlooked in water resource policy, such as that of the EU.
The study, by David Ellison, Martyn Futter and Kevin Bishop at the Swedish University of Agricultural Sciences (SLU), shows that reducing forest area reduces regional and continental rainfall. This needs to be recognized to obtain a fair picture of the forest role in the hydrologic cycle.
"Are forests good for water? An apparently simple question divides scientists in two camps -- those who see trees as demanding water and those who see trees as supplying water," said David Ellison who works in the Future Forests research program studying resource management. "This paper demonstrates that the difference between these two camps has to do with the spatial scale being considered."
From a local perspective, a tree is a consumer of water. But on a broader regional scale, forests supply the atmosphere with moisture that will become rainfall. Some dry areas depend almost entirely on rain that comes from forest-covered areas via the atmosphere.