We all know that trees can make some interesting sounds, but one biologist says those sounds are telling stories -- we just have to do is listen in the right way.

David George Haskell lives part time in Boulder and is a professor at The University of the South in Sewanee, Tennessee. He has spent years listening to trees all around the world and has learned to identify the voice of every species.

“The sound of wind in trees reveals the architecture of the tree," Haskell said. "Just like a human song has an acoustical component, then there’s the lyrics, and there’s a story that leads us to that point with all the meaning. Same thing with trees. We don’t think of them as songwriters, but they do have a distinctive acoustic signature.”


It’s not just wind and water hitting the bristles and leaves, but Haskell says there is a voice inside the tree, and he may be the first to ever capture that voice.

“And what I did was put a little ultrasonic detector on the twigs of a ponderosa pine tree, and this picks up the sounds that are way too high for the human ear to detect,” Haskell said. "There’s a tiny weenie little ultrasonic pop, release. Our ears can’t pick that up, but the ultrasonic detector can.”

“And it turns out that in the morning when the tree has nice wet roots, and water is flowing through its twigs, there’s not much ultrasound coming from it," said Haskell. "But later in the afternoon it starts to click and fizzle, and there’s all this craziness happening, and that’s because all the little columns of water that are running through the twig are breaking, and like a silken thread, snapping."

Haskell says there are hundreds of ultrasonic signals happening in a twig every hour, so what he has done is slowed that sound down with computer software and made it so it can be heard by the human ear.

“For me the ponderosa story is about drought and water. So it’s leaves are giving the sound of a tough old survivor of dry arid environments. And so that was the instrument that I chose for that particular species to get into its story,” Haskell said.


In his recently published book "The Songs of Trees", Haskell has identified the stories of several different trees across the planet. Each chapter is the story of an individual tree.

He says the songs of trees are full of wisdom and we can learn if we just listen.

“Trees live a very long time. They are rooted in one spot so they have to make it work," Haskell said. "They don’t have the option of leaving and renegotiating their interactions with their neighborhood in some other place. So the wisdom there is how to belong. How to belong in a network of life. Often in very challenging circumstances over centuries.”

David George Haskell will be giving a lecture about the songs of the trees on the University of Colorado campus on Tuesday at 7 p.m. The lecture is in the Old Main Chapel building and is open to the public.