The Sweet Song Of The Largest Tree On Earth

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Let’s take a trip to south central Utah into the Fishlake National Forest. Our destination– the largest tree on Earth, an aspen named Pando.

[WIND RUSTLING LEAVES]

The strange part of visiting Pando is it doesn’t really look like the world’s biggest tree. You’ll see rolling hills with thousands of tall, lean aspens swaying in the wind. And Pando is there, hiding in plain sight, because all of those tree trunks you’ll see aren’t actually tree trunks– no, technically, they’re branches. And that’s because Pando is one massive tree– sprawling more than 100 acres with 47,000 branches growing from it.

There’s a lot to learn about Pando, and my next guests turned to sound to understand the tree better and created an acoustic portrait to hear all the snaps and splinters and scuttles that happen in around the tree. Let me introduce them. Jeff Rice, a sound artist and co-founder of the Acoustic Atlas at the Montana State University Library. He’s based in Seattle. Lance Oditt, executive director of the nonprofit Friends of Pando, which is dedicated to preserving the tree. It’s based in Richfield, Utah. Welcome to Science Friday.

JEFF RICE: Thanks for having us.

LANCE ODITT: Thanks for having us, Ira– huge fans.

IRA FLATOW: Thank you. I described a picture of this tree. When I look at the picture of Pando, it does looked like a forest, Lance, and not a single tree. What’s going on here?

LANCE ODITT: Well, Pando is a tree of one. We haven’t known about it very long. But basically, it’s one seed, and that has split. And sort of like a giant algorithm, it’s spread out over time towards us in history.

IRA FLATOW: So all those trees are actually– as I said before, they’re branches.

LANCE ODITT: Yeah. So they’re genetically identical branches. They look like tree trunks to us. The botanical term is stems, technically. But most people think stems is like a weed and their yard or maybe something coming off a rosebush. These are fully sized parts of one tree that’s all connected by this massive root system.

IRA FLATOW: Yeah. I know– I’ve experienced that when I try to dig a hole for my plants and there are all these roots under there.

LANCE ODITT: You got it.

IRA FLATOW: Or branches. Are all aspens like this, Lance?

LANCE ODITT: No. But all aspen have the ability to self-propagate. The self-replication is actually a reproductive strategy. Often we see what are called aspen clones, typically, in response to some stress event. The tree will kind of in human terms– of course, it’s a tree– make a decision. Am I going to just try to do the pollen thing? Or am I going to just self-propagate? And so Pando’s been self-propagating towards us in history for about 9,000 years.

IRA FLATOW: 9,000 years. What does Pando mean? Why is it called Pando?

LANCE ODITT: Oh, yeah, there’s a lot of interesting history there around that, Ira. Typically, the people who discover something in the botanical world or in biology– they get to name it. Basically, they nicknamed the tree Pando. And that’s Latin for “I spread.” And they called it that because of how it spreads out over its landmass. It dominates the land that it calls home. It’s a stable aspen.

IRA FLATOW: Wow. OK, Jeff, let’s talk about recording Pando. You hauled out your microphones next to Pando. Why are you attracted to this? What did you do, actually?

JEFF RICE: Well, I’ve been recording sounds in the West for more than 20 years. And I’ve always loved the sound of aspen trees. I mean, it’s really a defining sound of the West for me. I love the delicate, trembling sound of it. And so that’s the first thing that attracted me. And I always liked recording aspen.

But just the chance to record the largest organism on Earth is just such an incredible opportunity. And I was interested in the challenges that posed. What does that mean to record such a large organism? And so I set about trying to record it from all different angles, from the leaves to the roots.

IRA FLATOW: So you actually stuck your microphone into the trunks of the trees down to the roots?

JEFF RICE: Yeah. I started recording traditional recordings, like ambisonic recordings of the soundscapes, the birds, and the leaves, and the weather. But there’s a great story about how we started recording the roots. I wanted to find another way of listening to Pando. And I had heard that trees make vibrations, and that people have recorded those vibrations. And I thought, wouldn’t it be interesting to record the roots of Pando? And I really didn’t know what that meant.

But I asked Lance if he could show me where I could find some roots that I might be able to hook a microphone to. And Lance knows everything about Pando. He’s been photographing the forest for years making one of the greatest photographic surveys of any tree. So he was able to show me some places where I could put my microphone. And we found a hole in one of the branches, essentially, at the base. And we were able to access the roots at that point and plug the hydrophone in, sort of like plugging into a socket, really.

IRA FLATOW: All right. Let’s take a listen. We have a recording of that. Let’s hear that now.

[LOW VIBRATIONS]

Wow. It sounds like– we New Yorkers– a subway train going by.

[LAUGHTER]

What are we listening to?

JEFF RICE: So that’s the sound of the leaves, I think, rattling on the tree in a thunderstorm. A thunderstorm rolled in, and it created a lot of wind that then blew the leaves that trembled. And the vibration of those leaves passed all the way through the tree right into the ground where we had the hydrophone. And it’s this delicate, trembling sound is strong enough that it actually vibrates the earth, in a sense.

LANCE ODITT: The story of that day– I mean, it’s still exhilarating just to think about it. And it’s great to be here with Jeff talking about that moment because we were just both like, wow, for the first time, we’re hearing– like we put a submarine in the ground, and we’re hearing Pando’s subterranean soundscape for the first time. And I already knew there was a lot of applications for this, but hearing it after spending, what, seven years in the tree was just– I was literally jumping up and down for joy, Ira.

IRA FLATOW: Amazing. Lance, I assume that every inch of Pando. So what was it like hearing the sounds from underground? Did you hear anything new?

LANCE ODITT: It was exciting. And yes, we heard a lot of new things. We heard the sound of a storm traveling through one of these branches that can reach 80 feet into the sky. And mind you, Pando’s homeland’s already at about 9,200 feet. It moves between about 8,900 and 9,200 feet. In terms of the sounds themselves, Ira, learned a lot. But when we first recorded it, me and Jeff were in the field. He’s like, come here. And it reminds me of that quote about what’s exciting about science. It’s not, oh, well, this is true or not true. It’s, what’s that?

IRA FLATOW: Yeah.

LANCE ODITT: And so we’re out in the field, and this happened to be a sunny day. And I’d scouted some locations for Jeff. And mind you, Pando’s root system is so dense that the trees don’t tend to break off at the foot or uproot, like you see a lot in the Pacific Northwest or other parts of the world. They just literally kind of break off at the ground like a matchstick. And so it’s hard to get into the root system. And Jeff’s like, what’s that? It was exactly that. It was, what’s that? And that was exhilarating.

IRA FLATOW: Well, I can bet. And I have a picture of Jeff walking around shaking a lot of branches figuring out what to record. Was it something like that?

JEFF RICE: Yeah, it was very organic. I mean, it was an exploration, really, of Pando. And I didn’t always know what I was going to find. And it was a real surprise that the second that I put on my headphones and started listening to the hydrophone, I heard a signal that I wasn’t sure what it was. And yeah, we started exploring and actually wondering, well, are we connected to the root system? And are these branches connected to each other by sound?

And we started banging on trees in different parts of the forest away from the hydrophone. I think Lance walked about 100 feet away from where we were set up with the microphone and started banging on a tree. And you could hear the sound passing through the ground into the hydrophone.

IRA FLATOW: Whoa. Whoa. Wow, let me stop you there because I know you recorded this. Let’s play a clip of this to hear what that sounded like.

[LOW THUMPING SOUNDS]

That thumps– they are subtle, but they are there. So the sounds are traveling almost 100 feet through the ground from tree to tree?

JEFF RICE: When we were doing the banging on the tree, we don’t know for sure that that banging was passing through the roots. It could have been passing through the soil. And there need to be some real scientific studies to determine that. This wasn’t a scientific expedition. It was an exploration of discovery. But it certainly shows that the branches– and the sound from the branches– it’s all interconnected. And I think that’s the takeaway. Whether it’s passing through the roots, they’re going to have to do some special studies to really determine that. But it doesn’t take away from the fact that it’s interesting and that it shows an interconnectedness.

IRA FLATOW: Yeah, all the more reason to go out and study Pando some more.

LANCE ODITT: Yeah, we’ve been doing some research on the background based off Jeff’s work to talk about how we can use sound. And there’s a lot of really exciting developments there that–

IRA FLATOW: Tell us. Tell us.

LANCE ODITT: Well, we have a few. It’s early, but I’ll give you an example. Pando’s homeland is in a graben. That’s the place where there’s a fault line. And it’s spreading apart because there’s hot magma below. So Pando’s landmass is littered with volcanic boulders and lava fields. So it’s really hard to get a subterranean picture of the tree. So imagine, then, based on Jeff’s work and some other work we’re doing with other researchers, that we could use sound to literally trace the root system of Pando and identify how all that works to better take care of the tree.

IRA FLATOW: Hmm. And so would you learn about the soil and water flow and things like that– or maybe even the wildlife living there underground?

LANCE ODITT: Absolutely. So yes, we can definitely look at soil quality. We can look at water. As far as wildlife, Jeff did record wildlife. And we have plans to set up audio conservation systems or bioacoustic stations in the tree this year to help us with wildlife. Then when you’re looking at water, nutrient transposition, disease, things like that, it’s reasonable to assume that trees that aren’t doing so well may have different frequencies because aspen are water-hungry trees. And so basically, each of these trunks is acting like a transducer. We may be able to use sound in a way. So beyond the subterranean, there’s a lot of work that this could help us with above ground as well, Ira.

IRA FLATOW: Interesting. Jeff, one of my favorite recordings you made is a little mystery critter that your hydrophone picked up. Let me play that clip for us now.

[ANIMAL BUZZING]

Like a buzzing– what is that?

JEFF RICE: That was the question I asked when I first heard it. These recordings– typically, I make them in the field, and I don’t get to hear them until I get back to the studio. And I was just listening in the studio to the underground recording. And suddenly, I heard this little voice. And I just was stopped in my tracks. I thought, what is that? Again, that question– what is that? And I think it might be a beetle or something. You’re always discovering new sounds when you make recordings, and there’s a lot to the underground soundscape.

IRA FLATOW: Lance, do you have any guesses of what that might be?

LANCE ODITT: So I feel somewhat confident to say that that was the sound of foxes in burrows. Our field crews are trained specifically to watch out for those because they’ll dig them under giant Juniper bushes. And they are very deep. So my assumption is it could have been a bird call. But most likely, it was foxes underground because, Jeff, correct me if I’m wrong– wasn’t that recorded during the storm?

JEFF RICE: It was recorded during a thunderstorm, although I would disagree that it’s a fox. This is the kind of thing that we go back and forth on, Ira.

IRA FLATOW: Yeah, I imagine.

JEFF RICE: It’s pure speculation as to what it is. But somebody told me that they thought it was a beetle, and that’s what it sounds like to me. But whatever it is, I call it the mystery creature. And it’s just an indication that there is a mystery world beneath the tree in the underground substrate.

IRA FLATOW: This is Science Friday. I’m Ira Flatow. In case you’re just joining us, I’m talking with Jeff Rice a sound artist and co-founder of the Acoustic Atlas– that’s at Montana State University Library– and Lance Oditt, executive director of the nonprofit Friends of Pando. And together, they created an acoustic portrait of the largest tree on Earth named Pando. What is the health of Pando? Is it flourishing? Is it being threatened?

LANCE ODITT: There is some research that has suggested that it’s dying. But what people have to remember is that Pando– it regenerates itself. And that’s a hormone cycle. And so the hormone cycle that sends regeneration has not ended. Well, we know that it’s still doing the hormone cycle that basically when a branch falls, a bunch of that hormone material goes back into the root. The root goes, hey, send another one up. I’ve got to balance energy production, regeneration, and defense.

In terms of collapse and things like that, Ira, there’s been some data that suggests that we’re heading in that direction. And there are models to abate that. And we are official partners with Fishlake National Forest dealing with those issues. But again, there are models for what is called aspen collapse, and Pando is nowhere near that by the best models or estimates.

So while there is a lot of headlines to that effect, we just need to know more. It’s early, Ira. It’s only been 14, 15 years since we just really said, oh my gosh, this thing is really here. It’s the largest tree in the world. It’s a tree that redefines tree– what a tree can be, what a tree can mean.

IRA FLATOW: Incredible. Jeff, obviously, as a radio person, I love sound. I’ve dealt with it most of my life. But what do you– as a sound recordist, what do you take away from all of this? Why do you take such care to record the sounds of our world?

JEFF RICE: Partly just fascination, but I always learn so much when I turn on my microphone. And the more I recorded Pando, the more I learned about it. And my goal was to really figure out, what’s the sound of one of the world’s largest organisms? And what I came away understanding was that sound is lots of different things.

It’s the birds that live in the tree. It’s the foxes and the insects underneath the ground. And this leaves and the earth shaking in the storm. It’s the weather. It’s all connected. And so I think that’s the true voice of Pando. And that’s what excites me about recording is just getting a sense of that interconnectedness of the soundscape.

[NATURE SOUNDS]

IRA FLATOW: Well, there’s that old Clint Eastwood song, “I Talk to the Trees.” And I guess now we could say the trees are talking back to us. So thank you both for taking time to be with us today– fascinating stuff.

JEFF RICE: Thank you.

LANCE ODITT: Thank you, Ira.

IRA FLATOW: Jeff Rice, a sound artist and co-founder of the Acoustic Atlas at Montana State University Library. He’s based in Seattle. And Lance Oditt, executive director of the nonprofit Friends of Pando based in Richfield, Utah.

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