Tree Power Could Save Forests From Fires

Oct. 1, 2008 -- Tree power might sound like a hippie battle cry, but scientists at the Massachusetts Institute of Technology have literally tapped into the tiny electrical current carried in trees and created a company, Voltree, to capitalize on it as a power source.

"People have known about this phenomena for many years and have tried to explain it by various exotic mechanisms," said Andreas Mershin, a postdoctoral researcher at MIT who is involved in the research.

"But the cause of it is a simple pH difference between the tree and the soil," said Chris Love, a senior in chemistry at MIT and Vice President of Voltree.

Working with the U.S. Forest Service, Voltree has created cheap sensors that use tree power to monitor temperature and humidity conditions inside forests. The goal is to give forest managers and firefighters better tools to predict and monitor fires.

Mershin and Love were initially skeptical of tree power but investigated it anyway. To debunk alternative explanations for the observed electrical charges, Mershin and Love put a potted, four-foot-tall ficus tree into MIT's copper Faraday cage (which blocks out external static electrical fields), stuck platinum electrodes into the soil and into the tree's tissue, and turned off the lights.

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Their instruments recorded a slight electrical charge.

To prove their own theory, that the charge was generated by the pH difference between the tree and the soil, the scientists created a range of soil pHs, from an acidic two to a basic 12, by adding hydrochloric acid and potassium hydroxide.