September 30, 2008 While specialist fire-fighting crews, squadrons of trucks and water-bombing helicopters all play an important role, access to reliable and timely information on fire behavior is among the most critical of all the tools used to combat wild fires and prevent the loss of life, livestock and property damage. Massachusetts Institute of Technology (MIT) researchers are now working on a system that uses energy from the trees themselves to power a network of temperature and humidity sensors that act as remote weather stations to aid in fire management.
While the odd phenomenon of "tree-power", or a sustained voltage difference between many plants and their surrounding soil has long been observed, the scientific basis for this effect has been the subject of debate. In a recently published paper on the subject, researchers from MIT's Center for Biomedical Engineering believe they have found the answer, postulating that the effect is mainly due to a difference in pH between parts of trees and the surrounding soil and ruling out other theories such as an electrochemical redox reaction (think 'potato batteries').
The practical application of this power source envisioned by researchers is to provide enough trickle-charge to self-sustaining temperature and humidity sensors in remote locations where replacement of batteries is costly and impractical. The energy produced would slowly charge an off-the-shelf battery within the sensors enable wireless transmission of signals four times a day. These signals would jump from one sensor to the next until they reached an existing weather station linked by satellite to a forestry command center and would transmit data immediately in the event of a forest fire.
Voltree Power is in the final stages of prototyping such a system with trials set for the spring on a 10-acre plot of land provided by the Forest Service. The company also sees applications beyond fire monitoring for its “bioenergy converter”, including remote environmental and agricultural sensing, climate science research and even Homeland Security and border protection, where trees could be fitted with sensors to detect potential threats like smuggled radioactive materials.
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