The evidence for plant communication is only a few decades old, but in that short time it has leapfrogged from electrifying discovery to decisive debunking to resurrection. Two studies published in 1983 demonstrated that willow trees, poplars and sugar maples can warn each other about insect attacks: Intact, undamaged trees near ones that are infested with hungry bugs begin pumping out bug-repelling chemicals to ward off attack. They somehow know what their neighbors are experiencing, and react to it. The mind-bending implication was that brainless trees could send, receive and interpret messages.
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Farmer’s study doesn’t mean that plants have neurons, or brains, or anything like the systems that animals use to communicate. We don’t do justice to them when we try to put their fascinating, alien biology into human terms, he said. But we may have dramatically underestimated their capabilities. As researchers begin to learn the language of plants, they are starting to get a whole new view of the leafy green world we live in.