Electricity branches out

MIT researchers are working on a system that harvests energy from trees to power a network of sensors.

The US Forest Service currently predicts and tracks fires with a variety of tools, including remote automated weather stations. But these stations are expensive and sparsely distributed.

Additional sensors on the trees themselves could help to save more trees by providing better local climate data to be used in fire-prediction models and provide early alerts to fire hazards. However, manually recharging or replacing batteries at often very hard-to-reach locations makes this impractical and costly.

The new sensor system avoids this problem by using the trees as self-sustaining power supplies. Each sensor is equipped with an off-the-shelf battery that can be slowly recharged using electricity generated by the tree it's on.

The system produces enough electricity to allow the temperature and humidity sensors to wirelessly transmit signals four times a day, or immediately if there's a fire. Each signal hops from one sensor to another, until it reaches an existing weather station that beams the data by satellite to a forestry command centre in Boise, Idaho.