Listen to the sounds of Pando, the largest living tree in the world

A stand of aspen trees
Pando stretches across more than 100 acres in Utah and is considered the world's largest tree. (Image credit: Jim Rice)

Researchers have recorded the sounds of the world's largest tree, a 13-million-pound (6 million kilograms) behemoth known as Pando that stretches across 106 acres (43 hectares) in southern Utah. The researchers think that listening to the recordings could give them a better understanding of the sprawling aspen’s health and any environmental changes that might affect it.

To the untrained eye, Pando resembles a forest made up of quaking aspen (Populus tremuloides) trees. However, it's actually a single clone comprising approximately 40,000 genetically identical stems (trunks) that are interconnected by a complex root system.

Last summer, Jeff Rice, a Seattle-based audio engineer, traveled to Pando, whose name means "I spread" in Latin. Using a hydrophone (a microphone normally used to pick up sounds underwater), he began recording the rustling of Pando's leaves in the wind, birds chirping in the canopy and critters scampering around — but he soon wanted to hear what was going on underground.

"There is this beautiful interconnectedness of Pando itself," Rice, who presented his recordings on May 10 at the 184th Meeting of the Acoustical Society of America, told Live Science. "Its sounds are so many different elements, but there's also this rich underground soundscape. There's more than just the trembling of the leaves. I started to discover that there was a lot going on there."

Rice teamed up with Lance Oditt, founder and executive director of Friends of Pando, a nonprofit organization dedicated to education and research about Pando. Working with Rice, who last summer served as its artist in residence, they began recording beneath the forest floor by dropping the hydrophone into what they dubbed the "Pando portal" — a gaping hole in one of the tree trunks. The result was a low, percussive rumbling similar to a guttural groan.

"I could reach down into the hole and connect the hydrophone directly to the roots," Rice said. "I plugged it in almost like a plug into a socket. We immediately started hearing interesting sounds, but what really stood out was a low, drone-like sound."

Related: The oldest tree in the world (and the 7 runner-ups)

To test their theory that the sound they were hearing was being carried via Pando's roots, they knocked on a branch roughly 100 feet (30 meters) away from the portal. The hydrophone recorded it as a thud.

"We could clearly hear the tapping," Oditt told Live Science. "This helps demonstrate that Pando is interconnected — and not just at the soil level. The root system is like a latticework underground."

Oditt is hopeful that getting a clearer image of what's rumbling beneath the surface could help scientists gain a better understanding of Pando, which is considered one of the largest organisms in the world.

For the past several summers, Oditt and a team of volunteers have been meticulously photographing nearly every square inch of the aspen clone using 360-degree cameras. Called the Pando Photographic Survey, the major undertaking enables anyone with an internet connection to virtually explore Pando. The project serves as a baseline to monitor changes to the tree over time.

The underground recordings offer new opportunities to better understand what has come to be known as the "trembling giant" in a way that's completely noninvasive. This includes mapping out Pando's root system, monitoring water flow and performing wildlife management that may help deter deer from eating the tree, which could hinder its regeneration.

"We can listen to any changes to the water and soil happening underground, and also use sound to trace its root system," Oditt said. "We could also possibly track disease and release ultrasonic sounds to help with the deer problem. We're not turning Pando into a speaker, but we want to help the tree to ward off problems."

Jennifer Nalewicki
Live Science Staff Writer

Jennifer Nalewicki is a Salt Lake City-based journalist whose work has been featured in The New York Times, Smithsonian Magazine, Scientific American, Popular Mechanics and more. She covers several science topics from planet Earth to paleontology and archaeology to health and culture. Prior to freelancing, Jennifer held an Editor role at Time Inc. Jennifer has a bachelor's degree in Journalism from The University of Texas at Austin.

  • Kooperkieri54
    Yes, You are right Pando, also known as the Trembling Giant, is a massive grove of quaking aspen trees (Populus tremuloides) located in Utah, USA. While it consists of multiple trees, they are genetically identical and connected through a common root system, making Pando the largest living organism on Earth. Researchers have been studying Pando using various methods, including the use of sound. Sound monitoring allows scientists to gain insights into the health, vitality, and interactions of the trees within the grove. By analyzing the sounds emitted by Pando, researchers can detect signals related to growth patterns, stress responses, and other aspects of the tree's biology.
    Reply
  • Chrisco
    So the movie Avatar show that this is actually true. Actually, many of us who farm or have gardens know the symbiotic relationship between plants. Many a stand of oaks are actually one tree with root spouts that can rise 300' away from the main tree. We also know that an injection of a radioactive substance in one tree can show up 1/2 mile away in another tree through interconnected roots and fungi.
    Reply
  • skynr13
    I think one can't be sure that the sounds they are recording are actually from the tree. The Earth could be producing this noise too. But I once saw a documentary on how scientists tried to understand trees by driving a nail into several trees and measuring the electrical signals they produced. Once they found this, they cut small branches and leaves off of them and were able to measure a response using the electrical signal produced that was something like a language. This could be done with these Aspen too! I couldn't find a link for that but here's one that is kinda' the same. https://www.sciencedaily.com/releases/2021/03/210316112257.htm
    Reply
  • Bonzadog
    Chrisco said:
    So the movie Avatar show that this is actually true. Actually, many of us who farm or have gardens know the symbiotic relationship between plants. Many a stand of oaks are actually one tree with root spouts that can rise 300' away from the main tree. We also know that an injection of a radioactive substance in one tree can show up 1/2 mile away in another tree through interconnected roots and fungi.
    You are quoting a film??? Avatar was a SF film nothing more.
    Reply
  • skynr13
    Bonzadog said:
    You are quoting a film??? Avatar was a SF film nothing more.
    Yea, I was kinda' confused by that Avatar comment too. But the rest of his comments are good. I'm a farmer and knowing your crop is like getting to know people. Some want more sun or water or fertilizer. They are like people, they need food, water and the bright sunshine to live. Maybe that's what they show in Avatar, but I've never seen that movie, so I don't know.
    Reply
  • bolide2
    They put a mic into a hollow trunk and recorded a rumbling sound. How do they know they weren't recording the same thing you get when you hold a sea shell up to your ear, i.e. ambient sound focused by the cavity?
    Reply