Ed Yong in The Atlantic:
Just as birders can identify birds by their melodious calls, David George Haskell can distinguish trees by their sounds. The task is especially easy when it rains, as it so often does in the Ecuadorian rainforest. Depending on the shapes and sizes of their leaves, the different plants react to falling drops by producing “a splatter of metallic sparks” or “a low, clean, woody thump” or “a speed-typist’s clatter.” Every species has its own song. Train your ears (and abandon the distracting echoes of a plastic rain jacket) and you can carry out a botanical census through sound alone.
“I’ve taught ornithology to students for many years,” says Haskell, a natural history writer and professor of biology at Sewanee. “And I challenge my students: Okay, now that you’ve learned the songs of 100 birds, your task is to learn the sounds of 20 trees. Can you tell an oak from a maple by ear? I have them go out, pour their attention into their ears, and harvest sounds. It’s an almost meditative experience. And from that, you realize that trees sound different, and they have amazing sounds coming from them. Our unaided ears can hear how a maple tree changes its voice as a soft leaves of early spring change into the dying one of autumn.”
More here.