阅读理解
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MIT researchers and their colleagues are working to fin d out whether energy from trees can power a network of sensors (传感器) to prevent spreading forest fires.
What they learn could also ra ise the possibility of using trees as silent guards along the nation’s borders to discover potential threats such as smuggled (走私的) radioactive materials.
The U．S. Forest Service currently predicts and tracks fires with a variety of tools, including remote automatic weather stations. But these stations are expensive and sparsely (稀疏地) distributed. Additional sensors could save trees by providing better local climate data to be used in fire prediction models and earlier warnings. However, recharging or replacing batteries by hand at very hardtoreach locations makes it i
