Spruce Juice

MIT scientists, Forest Service power wireless networks with just trees

Get ready to have your mind blown: MIT scientists have joined with the Forest Service to test a wireless network powered by the trees themselves. I know what you're thinking—I haven't ever been shocked by a pine either, but MIT scientists figured out that the imbalance in pH between a tree and the soil its planted in can actually generate a usable electrical charge. Check it:

"Its the imbalance in pH between the inside of the tree and the soil in which it was potted that generates a voltage," said (MIT professor Andreas Mershin). "You get about 59 millivolts for every step in pH mismatch."

What is significant about the voltage potential between a tree and its soil, according to Mershin, is that the metabolism of the tree itself works to maintain it; no matter whether its day or night, fall or spring, summer or winter, rain or sun.

U.S. Forest Service scientists hope to harness this charge to power remote sensors that help monitor weather conditions during fire season. In the past, sections of forest would have to be cleared to make way for solar panels, but now the low-power sensors can transmit data while being powered by the tree they're attached to. An underground electronics box will penetrate the tree with an electrode at its root, while another electrode stabs into the dirt. The tree-generated electricity runs through a wire attached to the trunk that connects to an above-ground sensor and wireless transmitter.

While the tree metabolism only generates tiny amounts of electricity, researchers have been able to boost it to 1 volt — enough to charge a battery, power a radio, and broadcast data across a network. Field testing for the first U.S. Forest Service tree-powered network will begin on 10 acres in spring 2009.

You know what this might mean: In 2011, when your iPod runs out of power in the backcountry, you'll be able to just plug it into the nearest spruce for a few minutes.

Man, the future rules.

— Ted Alvarez

Tall tale: Trees could power wireless networks (EE Times)