Listen to the sound of the heaviest living organism on earth, Pando

The sound of what is thought to be the world's heaviest living organism has been recorded and shared online. 

Located in Fishlake National Forest in south-central Utah, United States, Pando (Latin for "I Spread") is a natural colossus in the form of an aspen grove. While it resembles a forest, it is believed to be a single organism made up of over 47,000 aspen stems connected at the roots. Now, thanks to sound artist Jeff Rice, we're able to hear just how dense it really is.

Revealed at the 184th Meeting of the Acoustical Society of America earlier this month, 'Beneath the tree: The sounds of a trembling giant' is the result of Rice teaming up with Lance Oditt, the founder of the nonprofit group Friends of Pando. Comprising various acoustical and vibrational recordings made during a July 2022 thunderstorm, it's a feat of ecological ASMR featuring what could be millions of aspen leaves trembling in the wind.

In an interview with the Guardian, Rice said: “I recorded pretty much everything that I could possibly record,” noting that this included everything from leaves and birds, to foxes and the sound of ants moving over the branches.

As well as various microphones, central to the recording was the use of a hydrophone, which was placed inside a hole at the base of one of the branches and lowered to touch its roots. “It was just an experiment, and I honestly didn’t think I would get anything," said Rice. “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."

According to a report by Treehugger, Rice said: “Hydrophones don’t just need water to work. 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.”

Spread across 108 acres and estimated to weigh collectively 6,000 tonnes, research suggests that Pando has been regenerating for a very long time. "We have to keep in mind that it's been changing shape and form for, like, 9,000 years," said Oditt, speaking to NPR as part of their 3-Minute Listen podcast feature. "I call it the David Bowie problem. It's constantly reinventing itself, right?"

Speaking to Phys.org, Rice - who initially started the project in 2018 as part of a New York Times Magazine special issue - said: "The sounds are beautiful and interesting, but from a practical standpoint, natural sounds can be used to document the health of an environment. They are a record of the local biodiversity, and they provide a baseline that can be measured against environmental change."

While the recordings don't conclusively prove the theory of the fully connected root system, Rice told the Guardian: “I think the sound of Pando is really the sound of all of the parts of it. It’s the birds that are living in the tree, and it’s the insects, and it’s the wind in the leaves and it’s the vibration of the earth and the potential sound of the roots. And so I see it as really a great way of understanding the interconnectivity of Pando, and also soundscapes in general.”

Listen to the recording here.

Earlier this month, NASA unveiled an audio recording of plasma waves hitting Earth's magnetic field, one year after releasing an audio recording of a black hole to mark "Black Hole Week". The "sonification" arrived a month after NASA unveiled a recording that revealed that Mars has two speeds of sound. 

Later this year, the world's "most remote" club will open on a small island in the Inner Hebrides of Scotland.