Ash tree, Little Rouge woodland, ON (photo by Nina Munteanu)

“Trees are full of song,” writes David George Haskell in the May 10 online issue of Scientific American. “Wind clatters and hisses through leaves and needles, insects stridulate, ice rends weakened wood, people chatter on the street below, and mechanical noises reverberate within trunks.”

Haskell’s new book “The Songs of Trees”, explores the science and ethics of a dozen trees around the world. A professor of biology at The University of the South, he tells us to “step outside, attend to your ears…what do the sounds of trees reveal?”

In the Scientific American article, Haskell gives us ten ways to listen to trees, briefly excerpted here:

1. Fingers: “I hold two slabs of maple in my hands, each the weight of a heavy book. The blocks are hewn into wedges with surfaces rough enough to graze my skin…I tap the wood. My skin feels the answering reflections. One block has more clarity, it feels more bright, open, and lean muscled. The second is similar, yet tinged with granularity and turbidity.”
2. Soles of feet: “As the hickory log hits the blade, the saw’s judder and scream enter me thought the sawmill’s floor, a blast of vibratory energy.”
3. Electric caliper: “A metal clamp gently grasps a twig and measures diameter every 15 minutes. Over hours, days, weeks, the twig’s girth is scribed into electronic memory. On a 24-hour cycle, the twig pulses with a sun-powered heartbeat…On sun-happy branches, systole and diastole surge and draw back, the forest’s subsonic hum.”
4. Ultrasound: “A thumb-sized sensor presses against a pine twig’s thin bark. On a computer screen, a line scribes the number of high-pitched clicks and fizzles hitting the sensor, the sounds of water columns breaking inside the twig’s narrow-bored vessels. For the tree, these are the sounds of impending hunger…The silk-thin strands of water inside the plant’s vessels break with a snap.”
5. 

   Writer leans against a tree (photo by Nina Munteanu)

   Conversation: “Under branches, people gather. The tree is a nexus of human connection. In Manhattan, street vendors and pedestrians rest and chatter in the shade, out of the bruising jostle of the sidewalk.”

6. The sigh of indrawn breath and the flick of a switch: “The oxygen we inhale came from the trees and the oceans. We exhale and leaves snatch out unwanted carbon dioxide, then lodge it in wood, a timbered memory of breath. Click the light switch: coal burns, ancient memories are released.”
7. At a library desk: “Swish as I smooth my palm over the page of the scientific journal. I’m gazing at cellulosic sheets of tree, the wood’s stiffening lignin molecules purges by the paper-making process. Inked on their pages, data about the fate of forests…the land covered by forests is plunging…I turn the page, a crackle of fibers loose their complaint as the page buckles.”
8. Snoozing under a tree: “I wake from my nap to the smell of sun-warmed ponderosa resin. In the forest, relationships between trees and other species is a chemical process, so I listen with my nose. The golden sap between dark plates of ponderosa bark has the vigorous odor of rosin and turpentine: oily, acidic, and bright. The scent is a deterrent against attacking insects.”
9. Through insect sounds: “Clicks and rasps under the bark: beetle larvae auger the tree with jut-bladed mouths. The young insects swallow the fine sawdust, passing it to guts populated by symbiotic microbes. Woodpeckers listen, hoping to catch a sound that betrays an insect’s presence in the tree…The tree, too, listens. When the sounds of munching caterpillars are played to a tree, the plant releases defensive chemicals.”
10. Stop, listen: “Gusts of wind sonify plant diversity. Oak’s voice is coarse-grained, throaty; maples is sandy and light. These differences have their origins in plant evolution and adaptation. Drought-resistant oak leaves are thicker, tougher than the water-hungry maple.”

For the complete article, go to the original Scientific American article here.

Trees are the lungs of the planet. The world’s forests take up over a quarter of the carbon emitted by humanity, providing an essential role in buffering the effects of increased greenhouse gases in the atmosphere. Together with water and the hydrological cycle, trees act as air conditioners for the world. Preserving our forests, in tact, is an urgent need to maintain our planet’s welfare.

See my series of articles on why I love trees:

“Why I Love Trees: Part 1, Drinking Trees”

“Why I Love Trees: Part 2, Breathing Trees”

“Why I Love Trees: Part 3, Feeling Trees”

David George Haskell is a professor of biology at the University of the South and author of “The Forest Unseen”, winner of the 2013 National Academies’ Best Book Award and Pulitzer finalist.

Nina Munteanu is an ecologist, limnologist and internationally published author of award-nominated speculative novels, short stories and non-fiction. She is co-editor of Europa SF and currently teaches writing courses at George Brown College and the University of Toronto. Visit www.ninamunteanu.ca for the latest on her books.