We can now ‘hear’ the whispers of one of Earth’s largest and oldest living organisms, a forest made of a single tree known as Pando, which has 47,000 stems with identical DNA, spreading across 100 acres (40 hectares) in Utah. This expansive organism weighs in at 6,000 metric tons, making it the largest living thing on the planet by mass.
Pando is an ancient quaking aspen (Populus tremuloides) with tree-like stems that reach up to 24 meters (80 feet), possibly dating back 12,000 years. Through recordings released earlier this year, we can experience this enormous plant’s sounds for the first time.
“The findings are tantalizing,” said Lance Oditt, founder of Friends of Pando, when the project was unveiled in May 2023. “While it started as art, we see enormous potential for use in science. Wind, converted to vibration (sound) and traveling the root system, could also reveal the inner workings of Pando’s vast hidden hydraulic system in a non-destructive manner.”
Sound artist Jeff Rice experimented with placing a hydrophone in a hollow at the base of one of Pando’s stems and threading it down to the tree’s roots, not expecting much. However, he was surprised by what he heard.
“Hydrophones don’t just need water to work,” explained Rice. “They can pick up vibrations from surfaces like roots as well. When I put on my headphones, I was instantly surprised. Something was happening. There was a faint sound.”
During a thunderstorm, the sound grew louder, with an eerie low rumbling emerging through the hydrophone. “What you’re hearing, I think, is the sound of millions of leaves in the forest, vibrating the tree and passing down through the branches, down into the earth,” Rice noted during the 184th Meeting of the Acoustical Society of America, as reported by The Guardian.
The hydrophone also captured the sound of tapping on a branch 90 feet away, which wasn’t audible through the air, suggesting that Pando’s root system is interconnected. While this hints at how quaking aspens propagate through roots, proper experiments would be required to confirm that sound wasn’t traveling through the soil.
Rice’s work explores the sounds of Pando’s leaves, bark, and the broader ecosystem. Oditt hopes to use this data to map Pando’s root system and understand its complex relationships with the surrounding environment.
Tragically, Pando is deteriorating, and its decline is linked to human activities like clearing and predator control, which allow herbivore numbers to soar. This makes listening to ‘The Trembling Giant’ all the more important, as we might not have this unique voice to listen to much longer.
Earlier versions of this article were published in May 2023.
