Listening to the largest and oldest tree on Earth – what does it have to say?

In the heart of southcentral Utah, spanning an impressive 106 acres, lies a unique and awe-inspiring organism…a massive grove of aspen trees.

The Pando aspen grove may appear to be a forest at first glance, but in reality, it is a single organism with over 47,000 genetically identical aspen stems connected at the root. As the world’s largest tree by weight and land mass, Pando is a remarkable example of natural wonder. 

Studies indicate that this incredible organism has been regenerating for 9,000 years, making it one of the oldest living organisms on our planet.

An acoustic portrait of the world’s oldest tree

At the 184th Meeting of the Acoustical Society of America, Jeff Rice, a sound artist from Seattle, and Lance Oditt, founder of the nonprofit group Friends of Pando, will share their work in capturing a unique acoustic portrait of this botanical marvel. 

Their presentation, titled “Beneath the tree: The sounds of a trembling giant,” is scheduled for Wednesday, May 10, at 10:30 a.m. Eastern U.S. in the Great America 1/2 room, as part of the meeting taking place May 8-12 at the Chicago Marriott Downtown Magnificent Mile Hotel.

“Pando challenges our basic understanding of the world,” explained Rice. “The idea that this giant forest could be a single organism defies our concept of the individual. Its vastness humbles our sense of space.”

How the research was done

Rice initially recorded Pando’s leaves for The New York Times Magazine’s special issue “Listen to the World” in 2018. He returned in July 2022 as an artist-in-residence for Friends of Pando, the nonprofit group Oditt established in 2019. During his time there, Rice used various microphones to capture the sounds of Pando’s leaves, birds, and weather.

“The sounds are beautiful and interesting, but from a practical standpoint, natural sounds can be used to document the health of an environment,” Rice noted. “They are a record of the local biodiversity, and they provide a baseline that can be measured against environmental change.”

One particularly captivating aspect of the project was the sound of vibrations passing through the tree during a windstorm. Rice wondered if they could record the sound of Pando’s root system, which is believed to reach depths of up to 90 feet. 

Going deeper to listen to the oldest tree

Oditt, the executive director of Friends of Pando, identified several potential recording locations below the surface.

“Hydrophones don’t just need water to work,” Rice said. “They can pick up vibrations from surfaces like roots as well, and when I put on my headphones, I was instantly surprised. Something was happening. There was a faint sound.”

Although the sound has not been conclusively linked to Pando’s root system, a handful of experiments support the idea. Rice and Oditt demonstrated that vibrations can pass from tree to tree through the ground. When they tapped lightly on a branch 90 feet away, the hydrophone registered a low thump. Rice likened this to the classic tin can telephone.

“It’s similar to two cans connected by a string,” he explained. “Except there are 47,000 cans connected by a huge root system.”

A similar phenomenon was observed during a thunderstorm. As leaves moved more intensely in the wind, the signal recorded by the hydrophone also increased.

“The findings are tantalizing. 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 nondestructive manner,” Oditt said.

“Friends of Pando plans to use the data gathered as the basis for additional studies on water movement, how branch arrays are related to one another, insect colonies, and root depth, all of which we know little about today.”

A new frontier

The captivating sounds of Pando, captured by Rice and Oditt, open up a new frontier in understanding this ancient and mysterious organism. By exploring its unique acoustics, researchers can delve into the complex relationships and hidden mechanisms that govern the grove’s growth and survival. The findings have the potential to transform our understanding of not just Pando, but other organisms as well.

Moreover, the project highlights the importance of interdisciplinary collaboration between art and science. The partnership between Rice, a sound artist, and Oditt, a conservationist, demonstrates how seemingly unrelated fields can come together to unlock new insights into the natural world.

As the work on Pando continues, the researchers’ findings will not only deepen our understanding of this remarkable organism, but also serve as a testament to the power of curiosity and collaboration in the pursuit of scientific discovery.

More about aspen groves

Aspen groves are unique and fascinating ecosystems primarily composed of quaking aspen (Populus tremuloides) trees. Quaking aspens are widespread across North America, particularly in cooler regions with sufficient moisture. They can be found at various elevations, from sea level in Alaska to over 12,000 feet in the Rocky Mountains.

Aspens are known for their white bark and trembling leaves, which flutter in the wind due to their flattened petioles. The leaves have a characteristic shimmering effect that has earned the tree its nickname, “quaking aspen.” The trees typically grow to heights of 40-80 feet, with trunks measuring up to 3 feet in diameter.

One of the most remarkable features of aspen groves is their ability to reproduce through a process called vegetative propagation or clonal growth. While aspens can reproduce sexually through seeds, they primarily spread by sending up new shoots, called suckers, from their extensive root systems. These suckers share the same genetic material as the parent tree, creating a clonal colony where all the trees are genetically identical.

Over time, a single aspen tree can form a grove consisting of thousands of genetically identical trees, all connected through a shared root system. This clonal growth allows aspen groves to cover vast areas and dominate landscapes. A famous example is the Pando aspen grove in Utah, which is considered one of the largest and oldest living organisms on Earth.

Aspen groves provide essential habitat for a variety of wildlife, including birds, mammals, and insects. The trees’ leaves, bark, and buds serve as food sources for various species, while the groves offer shelter and nesting sites. In addition, aspens play a crucial role in maintaining biodiversity and promoting the health of the ecosystems they inhabit.

Aspen trees are also valuable for their role in water and soil conservation. Their extensive root systems help stabilize slopes, reduce erosion, and improve soil structure. Additionally, aspen groves contribute to the water cycle by absorbing and releasing water, influencing the availability and quality of water in their surrounding environment.

Unfortunately, aspen groves face several threats, including climate change, fire suppression, invasive species, and human development. Efforts are underway to protect and restore aspen ecosystems through active management, such as prescribed burning, mechanical thinning, and fencing to protect young trees from browsing animals.

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