derekmead writes: Harvesting electrical power from vibrations or other mechanical stress is pretty easy. Turns out all it really takes is a bit of crystal or ceramic material and a couple of wires and, there you go, piezoelectricity. As stress is applied to the material, charge accumulates, which can then be shuttled away to do useful work. The classic example is an electric lighter, in which a spring-loaded hammer smacks a crystal, producing a spark. Another example is described in a new paper in the Journal of Sound and Vibration, courtesy of engineers at Ohio State's Laboratory of Sound and Vibration Research. The basic idea behind the energy harvesting platform: exploit the natural internal resonances of trees within tiny artificial forests capable of generating enough voltage to power sensors and structural monitoring systems.