Trees may be able to protect themselves from forest fires by serving as living batteries—housing small devices, which would measure temperature and humidity and broadcast the data from tree-to-tree.
Current Forest Service fire sensors are spread widely, and gaps in the network can miss localized temperature and humidity changes. Researchers at MIT have proposed a solution to those gaps—using the trees themselves to power a web of additional sensors. The scientists, a group of students and teachers from MIT's Center for Biomedical Engineering, figured out that trees carry an electric charge due to a difference in acidity between the tree and the soil it sits in.
Batteries need to be replaced, but trees don't, meaning the network would sustain itself, saving costs to maintain and recharge sensors and allowing for a much larger and more sensitive monitoring grid. The group's results were published in the journal PLoS ONE, and they've already started a commercial company to develop the sensors that can harness that tree-power. According to their commercial website, they've developed a converter to power these weather sensors, which "parasitically harvests metabolic energy from any large plant without significantly harming it." They plan to test the network this spring.
Without significantly harming the tree sounds a bit off. The idea seems helpful but introducing parasites into a forest of trees sounds like it could easily become a problem.
They aren't introducing parasites into the forest, they are using energy from the trees in a parasitic manor to power the devices, in other words the electronics are the parasite.
This sounds like a great idea and could definitely help firefighters prevent large scale wildfires.
Does this mean we can now use trees as replacements for solar panels? Plant more trees to generate more power and they also help clean the air.
Don't expect to be seeing "Tree batteries" anytime. Stick a multimeter in a tree and you won't see much usable energy there - the strength of the current is proportional to the difference in acidity between the tree and the soil, and that's not a very big difference. That's why you don't see many tree-huggers dying of cardiac arrest from electric shock :D Damn hippy tree-huggers...
Besides, even if you harvested an entire forest for energy, solar panels and wind turbines still win out in terms of efficiency.
Still... it's kind of an amusing prospect that someone could hook up an outlet to a tree and enjoy some portable TV or something :D