Researchers have found a way to generate power by trees. In fact, researchers at the Massachusetts Institute of Technology found that plants can produce up to 200 Milli-volts of electrical energy. There have been several methods of getting electrical power from other natural resources like lemon and potato by creating a reaction between the food and two different metals. But trees power generation is a different mechanism.
Researchers have concluded that "tree power" generated by the trees is not enough to be used for household application like solar energy. However, the this tree power is enough to operate sensors as low-cost option for powering tree sensors that help detect environmental conditions or forest fires by providing better local climate data. The tree energy can also be used as electronic output to keep track of a tree's health.
Some other ambitious possibilities include using trees as silent sentinels along the nation's borders to detect potential threats such as smuggled radioactive materials, automated weather stations.
To generate power from trees, a number of many methods were tested by a research team at Massachusetts Institute of Technology apart from the famous simple electrochemical redox reaction (the type that powers the 'potato batteries' common in high school science labs, http://en.wikipedia.org/wiki/Lemon_battery).
