From Tree to Shining Tree

Summary

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Radiolab – "From Tree to Shining Tree"

Date: July 30, 2016 | Hosts: Jad Abumrad & Robert Krulwich
Main Guests: Dr. Suzanne Simard (Forestry Professor, UBC), Jennifer Frazer (Science Writer)

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Episode Overview

This episode delves into the secretive, astonishing underground world of trees and fungi—exploring the so-called "Wood Wide Web." Hosts Jad and Robert, joined by experts, uncover how forests are vast communities of interlinked organisms that trade food, messages, and even defend each other. Through captivating storytelling and illuminating analogies, the episode overturns assumptions about forests as mere collections of competing trees, revealing extraordinary cooperation beneath the soil.

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Key Discussion Points and Insights

1. Childhood Curiosity and the Discovery of Roots

• Suzanne Simard’s Origin Story: Suzanne, a forestry professor, recalls her childhood exploring the British Columbia rainforest, literally tasting the forest floor ([02:52]).
• Pivotal Incident: A family dog, Jiggs, falls into an outhouse, prompting the family to dig him out and expose a mat of intertwined roots—Simard’s first encounter with the complexity beneath the forest ([05:20]).
  • Quote:

  “Jigs had provided this incredible window for me, ... how many different colors they were, how many different shapes there were, that they were so intertwined, as abundant as what was going on above ground. It was magic for me.”
  —Suzanne Simard ([05:58])

2. The Underground Connections – Early Research

• Industrial Forestry and Unexpected Observations:
  • Simard notices that Douglas fir trees grow healthier alongside birch; removing birch led to fir decline ([07:28]).
  • Hypothesis: There is some form of underground cooperation.
• Radioisotope Experiment:
  • Trees (fir, birch, cedar) are labeled with radioactive gas to track how “food” moves.
  • Discovery: Trees share resources underground, with one tree connected to up to 47 others ([09:00]–[10:03]).
  • Quote:

  “It’s just this incredible communications network that... people had no idea about in the past because we didn’t know how to look.”
  —Suzanne Simard ([10:14])

3. The "Wood Wide Web" Explained

• Science Writer Jennifer Frazer introduces the memorable term “Wood Wide Web” for this network ([10:51]).
• Is it Just Roots? No, it’s more than that—a third organism is involved.

4. Meet the Real Connectors: Fungi

• Field Trip to the Bronx Botanical Garden:
  • Hosts and experts look for and find fine, white fungal threads—the real networkers ([13:01]–[13:10]).
  • Physical Scale: Up to 7 miles of fungal “threading” in a pinch of dirt ([13:39]).
• Fungi are Not Plants:
  • Biological Category: Fungi are more closely related to animals than plants ([13:54]).
  • Ancient Origins: Fossils show fungi-plant association going back 400 million years ([14:31]).

5. How the System Operates: Mutualism, Mining, and Murder

• Mutual Support System:
  • Fungi access minerals/water in the soil and swap them for sugar (carbon) produced by trees ([15:31]–[19:16]).
  • Quote:

  “The fungi need sugar to build their bodies the same way that we use our food to build our bodies.”
  —Jennifer Frazer ([18:15])

• How Fungi Acquire Minerals:
  • Mining: Secreting acids to bore tunnels into rocks and extract mineral nutrients (nitrogen, phosphorus, etc.) ([24:03]–[24:51]).
  • Hunting: Some fungi trap and kill tiny soil dwellers (springtails) to absorb their nitrogen ([25:25]–[26:55]).
    • Gruesome Image: Springtails found with fungus threads growing inside them—still alive ([26:36]).
  • Fishing: Fungi transport nutrients from decomposing fish (like salmon left by bears) into trees, making up to 75% of the nitrogen in some trees ([27:54]–[28:33]).

6. The Economy of the Forest: Scale and Reciprocity

• Sugar Trade Scale: A tree may send 20–80% of its sugar into the underground network to feed fungi ([29:00]–[29:14]).
• The “Bank Account” Model:
  • Trees bank resources in fungi and retrieve them when needed—resources flow back and forth ([29:46]–[30:10]).
  • Warning System: Trees send alert chemicals through the fungal network if they’re attacked or under environmental stress ([30:16]–[31:05]).
    • Quote:

    “If a tree’s injured, it’ll cry out in a kind of chemical way... and warn neighboring trees or seedlings.”
    —Suzanne Simard ([30:25])

7. Adaptation, Resilience, and Intelligence?

• Resource Redistribution in Stress:
  • Dying trees may move their carbon to better-adapted, often different, trees—boosting forest survival ([31:27]–[32:53]).
  • Quote:

  “There’s an intelligence there that’s beyond just the species.”
  —Suzanne Simard ([33:08])

• Plant Intelligence Controversy:
  • Simard, when asked, recognizes the parallel to brains or nervous systems, though mainstream science remains cautious ([33:43]–[34:06]).
  • Quote:

  “Physically, when we look at the belowground structure, it looks so much like a brain... there are so many parallels.”
  —Suzanne Simard ([33:43])

8. The Forest as a Superorganism

• Jennifer Frazer likens the forest to a superorganism, like a honeybee colony.
  • “It’s almost as if the forest is acting as an organism itself.” ([34:06])

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Notable Quotes & Memorable Moments

• “Jigs had provided this incredible window for me... it was magic for me.”
  —Suzanne Simard ([05:58])

• On fungal mining:

  “They secrete acid and these acids come out and they start to dissolve the rock. It’s like they’re drilling and the fungus actually builds a tunnel inside the rock and... can mine them.”
  —Jennifer Frazer ([24:37])

• “Springtail murder” revelation:

  “[The] fungus ate them. In the little springtail bodies, there were little tubes growing inside them... [still alive].”
  —Jennifer Frazer ([26:36])

• “Salmon in tree rings” discovery:

  “The fungi... drink the salmon carcass down and then send it off to the tree, and the tree has evidence of its salmon consumption.”
  —Robert Krulwich ([27:54])

• Underground chemical warnings and cooperation:

  “So you can see this is like a game of telephone. One tree goes, 'Oh,' and the next one goes, 'Oh,' ... and then they do stuff.”
  —Robert Krulwich ([30:48])

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Timestamps for Important Segments

• Intro and Setting Up the Forest Scene – [01:59]–[02:52]
• Simard’s Origin Story (Jiggs, Roots, and Wonder) – [02:52]–[06:19]
• Clearcutting and the First Suspicion of Networked Forests – [06:31]–[08:13]
• Radioactive Gas Experiment & Discovery of Underground Network – [08:13]–[10:14]
• Introduction of the “Wood Wide Web” – [10:51]–[11:53]
• Bronx Botanical Garden: Discovering Fungi – [11:53]–[13:39]
• Fungal Mutualism, Mining, and Predation – [15:31]–[27:07]
• Resource Banking, Warning Signals, “Intelligence” – [29:46]–[33:08]
• Forest as Superorganism Discussion, Plant Intelligence – [34:06]–[35:30]

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Tone and Language

The tone throughout is playful, curious, and slightly irreverent—hallmarks of Radiolab's storytelling style. Interviewees speak with wonder and awe, and technical details are broken down with vivid analogies and humor.

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Takeaway

"From Tree to Shining Tree" reimagines forests as communities shaped by secret partnerships, cunning resource deals, and something that feels awfully like social intelligence. Far from being lonely, rival giants, trees are participants in a bustling, collaborative "internet" mediated by ancient fungi—a Wood Wide Web that supports, warns, and adapts for the good of the whole forest.

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If you've never before marveled at the ground beneath your feet, this episode leaves you with a brand new respect for the unseen alliances and dramas beneath the forest floor.

Transcript

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[Robert Krulwich]

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[Jennifer Fraser]

Okay.

[Jad Abumrad]

All right. Okay. All right.

[Robert Krulwich]

You're listening to Radiolab Radio Lab from wnyc.

[Jad Abumrad]

Hey, I'm Jad Abumrad.

[Robert Krulwich]

I'm Robert Krulwich.

[Jad Abumrad]

This is Radiolab. Very good to actually be back here talking to you.

[Robert Krulwich]

Yes. It's been a while. Yes. Where have you. Tell those people who might have missed what you were doing, what you've been doing, so they will not miss it.

[Jad Abumrad]

We just finished our first mini season of our first spinoff called More Perfect.

[Robert Krulwich]

When are you going to have part two?

[Jad Abumrad]

Part two is coming soon. I don't know. Not tomorrow. Okay, but not long because there are definitely stories to tell for sure. And you know, and if you haven't checked it out, check it [e-mail] moreperfect. We're really proud of it.

[Robert Krulwich]

So let me rescue you from this awkward situation by bringing you back to Radio Lab, where I'd like to begin by building a tall, dark, dense, green forest. Imagine towering trees to your left, to your right. I need a bird. Not a lot of birds actually. And a little wind. So just sound. Sound, yeah. Birds, Please. Birds.

[Jad Abumrad]

Why? We haven't even started this.

[Robert Krulwich]

What do you mean, why? Isn't this what you do? You give me like, I want wind birds.

[Jad Abumrad]

I'm not like your sound puppet here, but I can't.

[Robert Krulwich]

How do I. All right, never mind this story.

[Jad Abumrad]

You'll get your sound at some point.

[Robert Krulwich]

Begins with a woman, or at the time, actually, she was a very little girl who loved the outdoors. And I mean really loved the outdoors.

[Suzanne Simard]

When I was a little kid, I would be in the forest, and I just eat the forest floor. And I know lots of kids do that, but I was asleep.

[Robert Krulwich]

You mean you got down on all fours and just.

[Suzanne Simard]

Yeah, I would just eat.

[Robert Krulwich]

This is Suzanne Simard.

[Suzanne Simard]

And so my mom always talks about how she had to constantly be giving me worm medicine because I always had worms.

[Robert Krulwich]

She's a forestry professor at the University of British Columbia and might as well start the story back when she was a little girl.

[Suzanne Simard]

Well, when I was a kid, I grew up in the rainforests of British Columbia, and my family spent every summer in the forest.

[Robert Krulwich]

And her family included a dog named Jiggs.

[Suzanne Simard]

And so in this particular summer, when the event with Jiggs happened.

[Robert Krulwich]

What kind of dog is Jiggs, by the way?

[Suzanne Simard]

He was not a wiener dog. He was a. What was he?

[Robert Krulwich]

You don't know what your dog was.

[Suzanne Simard]

Not a basset hound, but he was a beagle. Beagle, yeah. He was a curious dog.

[Robert Krulwich]

And on this particular day, she's with the whole family. They're all out in the forest. It was summertime, and Jiggs at some point just runs off into the woods, just maybe to chase a rabbit, whatever. A couple of minutes go by, and.

[Suzanne Simard]

All of a sudden we could hear this barking and yelping, and we were all like, oh, my goodness, Jigs is in trouble. And so the whole family and uncles and aunts and cousins, we all rush.

[Robert Krulwich]

Up there, but they follow the sound of the barking, and it leads them to an outhouse. And when they go in, there is.

[Suzanne Simard]

Jigs at the bottom of the outhouse, probably six feet down at the bottom of the outhouse pit.

[Robert Krulwich]

Oh, dear.

[Suzanne Simard]

Where we've all been, you know, doing our daily business. Yeah, he'd fallen in. He's looking up at us quite scared and very unhappy that he was covered in. Oh, and toilet paper. And of course, we had to get Jigs out. I mean, Jigs was part of the family.

[Robert Krulwich]

Yes. And since he was so deep down.

[Suzanne Simard]

In there, we had to dig from.

[Robert Krulwich]

The sides to sort of like widen.

[Suzanne Simard]

The hole, basically expanding it from a kind of a column of a pit to something that we could actually grab onto his front legs and pull him out. And so we're digging away, and Jiggs was, you know, looking up with his paws, you know, looking at us, waiting.

[Robert Krulwich]

And they're digging and digging and digging him. And all of a sudden, she says she looks down into the ground, and she notices that all around them, where the soil has been cleared away, there are roots upon roots upon Roots in this thick, crazy tangle.

[Suzanne Simard]

We're sitting on the exposed root system, which is like. It is like a mat. It's like. It's just a massive mat of intertwining, exposed roots that you could walk across to never fall through.

[Robert Krulwich]

She says it was like this moment where she realizes, oh, my God, there's this whole other world right beneath my feet.

[Suzanne Simard]

Jigs had provided this incredible window for me, you know, in this digging excapade, to see how many different colors they were, how many different shapes there were, that they were so intertwined, as abundant as what was going on above ground. It was magic for me.

[Robert Krulwich]

So what's the end of the story? Did Jigs emerge?

[Suzanne Simard]

Jiggs emerged. We pulled Jiggs out and we threw him in the lake with a great deal of yelping and cursing and swearing, and Jiggs was cleaned off.

[Robert Krulwich]

But that day with the roots is the day that she began thinking about the forest that exists underneath the forest. Now, if you Fast forward roughly 30 years, she then makes a discovery that I find kind of she's working in the timber industry at the time. This is, by the way, what her entire family had done. Her dad and her grandparents.

[Suzanne Simard]

And when I came on the scene in the 1980s as a forester, we were into industrial, large scale clear cutting in Western Canada. Huge machines, loaders and cats.

[Robert Krulwich]

She says a timber company would move in and clear cut an entire patch of forest and then plant some new trees.

[Suzanne Simard]

And, you know, my job was to track how these new plantations would grow. And.

[Robert Krulwich]

And she says she began to notice things that, you know, one wouldn't really expect. Like trees of different species are supposed to fight each other for sunshine, right? You've heard that?

[Jad Abumrad]

Yeah, absolutely.

[Robert Krulwich]

And they have to.

[Jad Abumrad]

They shade each other out.

[Robert Krulwich]

They shade each out, and they fierce, you know, they push each other away so they can get to the sky. But she was noticing that in a little patch of forest that she was studying, if she had, say, a birch tree next to a fir tree, and if she took out the birch, the.

[Suzanne Simard]

Douglas fir became diseased and died. There was some kind of benefit from the birch to the fir. There was a healthier community when they were mixed. And I wanted to figure out why.

[Robert Krulwich]

Well, of course, there could be a whole, any number of reasons why, you know, one tree is affected by another. But she had a kind of, maybe you'd call it a Jigsian recollection, a flashback. Yes, because she knew that scientists had proposed years before that maybe there's an underground economy that exists among trees that we can't see. And she wondered whether that was true.

[Suzanne Simard]

And so I designed this experiment to figure that out. It was a simple little experiment.

[Robert Krulwich]

So here's what she did. She went into the forest, got some.

[Suzanne Simard]

Trees, Douglas fir, birch and cedar. And then I would cover them in plastic bags. So I'd seal the plant, the tree in a plastic bag, and then I would inject gas, so tagged with an isotope, which is radioactive.

[Robert Krulwich]

So these trees were basically covered with bags that were then filled with radioactive gas.

[Suzanne Simard]

Yeah, which the trees would just suck up through photosynthesis.

[Robert Krulwich]

So now they had the radioactive particles inside their trunks and their branches.

[Suzanne Simard]

We had a Geiger counter out there. As soon as we labeled them, we used the Geiger counter to ran it up and down the trees. And we could tell that they were hot. They were boo, boo, boo, boo, boo.

[Sponsor Voice]

Right.

[Robert Krulwich]

And the idea was she wanted to know, like, once the radioactive particles were in the tree, what happens next? Would they stay in the tree or would they go down to the roots? And then what happens? And what she discovered is that all these trees, all these trees that were of totally different species, were sharing their food underground. Like, if you put food into one tree over here, it would end up in another tree maybe 30ft away over there, and then a third tree over here, and then a fourth tree over there and a fifth tree over there. There. 6th, 7th, 8th, 9th, 10th, 11th. All in all, turns out one tree was connected to 47 other trees. All around was like a huge network.

[Suzanne Simard]

And we were able to map the network. And what we found was that the trees that were the biggest and the oldest were the most highly connected. And so we, you know, we identified these as kind of like hubs in the network.

[Robert Krulwich]

And when you look at the map, what you see are circles sprouting lines and then connecting to other circles, also sprouting lines. And it begins to look a lot like an airline flight map, but even more dense.

[Suzanne Simard]

It's just this incredible communications network that, you know, people had no idea about in the past because we didn't know how to look.

[Jennifer Fraser]

It's definitely crazy. I mean, you're out there in the forest and you see all these trees and you think they're individuals, just like animals. Right. But no, they're all linked to each other.

[Robert Krulwich]

This is Jennifer Fraser. She's a science writer and I write.

[Jennifer Fraser]

A blog called the Artful Amoeba at Scientific American.

[Guest/Additional Commentator]

I like your title.

[Jennifer Fraser]

Thank you.

[Robert Krulwich]

I spoke to her with our producer, Latif Nasser, and she told us that this network has developed A kind of a nice, punny sort of name.

[Jennifer Fraser]

The Wood Wide Web.

[Robert Krulwich]

The what?

[Jennifer Fraser]

The Wood Wide Web.

[Robert Krulwich]

You mean like the World Wide Web? It's now the Wood Wide Web. It sounds a little like Elmer Fudd. The Wood Wide Web.

[Jennifer Fraser]

Yep.

[Jad Abumrad]

So this Wood Wide Web, is this just like the roots? Like what you saw in the outhouse?

[Robert Krulwich]

No, no, no, no, no, no. It's far more exciting than that. And sophisticated and interesting and astonishing.

[Jennifer Fraser]

What?

[Robert Krulwich]

No, it is. It involves a completely separate organism I haven't mentioned yet. I mean, this is going places.

[Jad Abumrad]

What creature? Where are we going?

[Robert Krulwich]

I'm not gonna tell you. I'm gonna just go there. We went and looked for ourselves. I don't know where you were that day. Annie McEwan. Stephanie Tam, our intern. Annie's our producer. We decided all to go to check it out for ourselves. This thing I'm not telling you about. We went to the Bronx, to the Botanical Gardens, because we knew that's how.

[Jad Abumrad]

Far you have to travel here in New York to get to actual greenery.

[Robert Krulwich]

Actually, the most beautiful green sward New York has. And when we went up there, there was this tall man waiting for us, an expert.

[Jennifer Fraser]

Is that Roy?

[Robert Krulwich]

That is Roy. His name is Roy Howling. And Roy, by the way, comes out with this strange. It's like a rake. He's got a trowel, but it has, like, an expandable. It's a truffle rake. Oh, it's an extension. Oh, listen to that.

[Jad Abumrad]

Oh, that sounds dangerous.

[Robert Krulwich]

And so we're up there in this old forest with this guy. So there's an oak tree right there. It should have some. And he starts digging with his rake at the base of this tree. He shoves away the leaves, he shoves away the topsoil.

[Jennifer Fraser]

Can the tree feel you ripping the.

[Robert Krulwich]

Roots out like that? I hope not. And so now we're down there, pulled out a sapling root of some sort. It's just getting started. They're called feeder roots. We're carefully examining the roots of this oak tree on our knees, with our noses in the ground, and we can't see anything. I mean, I see the dirt. Do you see anything white yet? Do you see anything white and stained? Like I said, it's early in the season. So he says something about, that's the wrong season. I said, okay, so this is just stupid. But then finally. Do you have the lens? He gives us a magnifying glass. You know, one of those little jewelers, glasses, handheld. Have a look there. And he hands it to Annie.

[Jad Abumrad]

Wow.

[Robert Krulwich]

You see it there.

[Suzanne Simard]

Oh, yeah, the white.

[Robert Krulwich]

Let me.

[Jad Abumrad]

Can I see?

[Robert Krulwich]

You go for it. Oh, my gosh. I do see them.

[Jad Abumrad]

What do you see?

[Robert Krulwich]

Little white threads attached to the roots, smaller than an eyelash, maybe just a tenth the width of your eyelash, but white, translucent and hairy, sort of. And while it took us a while to see it, apparently these little threads in the soil, they're everywhere. And when you measure them, like one study we saw found up to seven miles of this little threading in a pinch of dirt.

[Jad Abumrad]

What?

[Guest/Additional Commentator]

A pinch?

[Jennifer Fraser]

Mm.

[Jad Abumrad]

What is this thing? Is it like. Is it a plant? What is it?

[Robert Krulwich]

What kind of creature is this thing?

[Jad Abumrad]

Yes, what is it?

[Robert Krulwich]

This is the fungus, which, by the way, is definitely not a plant.

[Jennifer Fraser]

They're some other kind of category, and for a long time they were thought of as plants. But now we know, after having looked at their DNA, that fungi are actually very closely related to animals. They're one of our closest relatives, actually.

[Robert Krulwich]

Now, back in the day, this all has a history. Of course, when people first began thinking about these things, we're talking in the 1600s, they had no idea what they were or what they did. But ultimately they figured out that these things were very ancient. Because if you look at 400 million year old fossils of some of the very first plants, you can see even.

[Jennifer Fraser]

In the roots of these earliest land.

[Robert Krulwich]

Plants, you can see those threads.

[Jennifer Fraser]

This is a really ancient association.

[Robert Krulwich]

And then later, scientists finally looked at these things under much more powerful microscopes and realized the threads weren't threads really. They were actually tubes, hollow.

[Jennifer Fraser]

These little tubes.

[Jad Abumrad]

Tubes.

[Jennifer Fraser]

Tubes. And the tubes branch, and sometimes they reconnect.

[Robert Krulwich]

So there seemed to be, under the ground, this fungal freeway system connecting one tree to the next, to the next, to the next. People speculated about this, but no one had actually proved it in nature, in the woods, until Suzanne shows up.

[Suzanne Simard]

And there was a lot of skepticism at the time. But over the next two decades, we did experiment after experiment after experiment that verified that story.

[Jad Abumrad]

Wait a second, wait a second. What is this? Why is this network even there? Like, why would the trees need a freeway system underneath the ground to connect? And why would the fungi want to make this network?

[Jennifer Fraser]

Why are they going to this trouble of creating this big network? Yeah, well, they do it because the tree has something the fungus needs and the fungus has something the tree needs.

[Robert Krulwich]

Let me just back up for a second so that you can. To set the scene for you.

[Jad Abumrad]

Yeah.

[Robert Krulwich]

When you go into a forest, you see a tree, a tall tree. So what does the tree do?

[Jad Abumrad]

What's Its job.

[Robert Krulwich]

What's its job? It soaks in Sunshine, takes the CO2 out of the air. Carbon dioxide, which has, of course, carbon C in it.

[Jad Abumrad]

The oxygen.

[Robert Krulwich]

Yeah.

[Jennifer Fraser]

And it keeps the C. Carbon, which is science speak for food, it turns.

[Robert Krulwich]

That carbon into sugar, which it uses to make its trunk and its branches. Anything thick you see on a tree is just basically air made into stuff.

[Jad Abumrad]

Carbon and sugar are the same thing.

[Robert Krulwich]

Yeah. You can think of carbon as basically the sugar that builds the tree. However, if that's all they had was carbon, it would only be this tall. Oh, that's Roy again. He's holding his hand. Maybe a. Off the ground, it would be a teeny tree. It would be smaller. So if all a tree could do is get carbon from the air, you'd have a tree the size of a tulip. A floppy tulip.

[Suzanne Simard]

Huh.

[Robert Krulwich]

A tree needs something else. And what a tree needs are minerals.

[Jennifer Fraser]

Minerals from the soil. Very similar to the sorts of vitamins and minerals that humans need.

[Robert Krulwich]

What kind of minerals does a tree need?

[Suzanne Simard]

Like nitrogen and phosphorus, magnesium, potassium and calcium and copper.

[Jad Abumrad]

Why? What do these do for the tree?

[Robert Krulwich]

Can a tree stand up straight without moving minerals, or can it can't. It can't.

[Suzanne Simard]

No. So, for example, lignin is important for making a tree stand up straight. And lignin is full of nitrogen. But also compounds like nitrogen is important in DNA.

[Jad Abumrad]

Right.

[Suzanne Simard]

It's an integral part of DNA.

[Robert Krulwich]

Oh, so, like, crucial. If I want to be a healthy tree and reach for the sky, then I need rocks in me somehow. Liquid rocks.

[Suzanne Simard]

You do? You need the nutrients that are in.

[Robert Krulwich]

The soil and gnats where the fungus comes in.

[Jennifer Fraser]

The fungus has this incredible network of tubes that it's able to send out through the soil and draw up water and mineral nutrients that the tree needs.

[Guest/Additional Commentator]

Wait, I thought. I thought tree roots just sort of did like I thought. I always imagined tree roots were kind of like straws. Like, the tree was, like, already doing that stuff by itself. But it's the fungus that's doing that stuff.

[Jennifer Fraser]

Yes. In a lot of cases, it is the fungus, because tree roots and a lot of plant roots are not actually very good at doing what you think they're doing.

[Robert Krulwich]

She says the tree can only suck up what it needs through these, you know, mostly through the teeny tips of its roots. And that's not enough bandwidth.

[Jad Abumrad]

Wait, so, okay, so the fungus is giving the tree the minerals?

[Robert Krulwich]

Yeah.

[Jad Abumrad]

What is the tree giving back to the fungus?

[Robert Krulwich]

Remember I told you how trees make sugar?

[Jad Abumrad]

Yeah.

[Robert Krulwich]

So that's what the tree gives the fungus sugar.

[Jennifer Fraser]

The fungi need sugar to build their bodies the same way that we use our food to build our bodies.

[Suzanne Simard]

They can't photosynthesize, they can't take up CO2. And so they have this trading system with trees.

[Robert Krulwich]

She says what'll happen under the ground is that the fungal tubes will stretch up toward the tree roots, and then.

[Suzanne Simard]

They'Ll tell the tree with their chemical language, I'm in the neighborhood. Will you soften your roots so that I can invade your root system? And the tree gets the message, and it sends a message back and says, yeah, I can do that. Like, I can start softening up my cell walls and make room for you.

[Robert Krulwich]

And then those little tubes will wrap themselves into place. It's a little white thread. You can see the white stuff is the fungus. And we saw this in the Bronx, the little threads just wrapping themselves around the tree roots, the last kind of part of the root, and tangled just around the edge. And it's in that little space between them that they make the exchange.

[Jad Abumrad]

What exchange would that be, Robert?

[Robert Krulwich]

That would be sugar, minerals, sugar, minerals, sugar, minerals, sugar, minerals, sugar, minerals, sugar, minerals, sugar, minerals, sugar, minerals, and so on.

[Sponsor Voice]

What?

[Jad Abumrad]

I forgot to ask you something important. Yes. If the tube system is giving the trees the minerals, how is it getting it the minerals?

[Robert Krulwich]

How's it getting the minerals?

[Jad Abumrad]

Is it just pulling it from the soil?

[Robert Krulwich]

Well, that's a miracle. That's like. That is. I gotta say, doing this story like this is the part that knocked me silly.

[Jad Abumrad]

We'll be right back.

[Robert Krulwich]

Hello, this is Ricardo from beautiful Monroe, New York. Radiolab is supported in part by the Alfred P. Sloan foundation, enhancing public understanding of science and technology in the modern world. More information About [e-mail].

[Sponsor Voice]

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[Commercial Narrator]

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[Guest/Additional Commentator]

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[Sponsor Voice]

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[Jennifer Fraser]

Right?

[Sponsor Voice]

You'll find specific research backed techniques. It's the science of sexual generosity in action. See what they discovered today@omg yes.com. that's omg yes.com.

[Jad Abumrad]

I'm Jad Abumrad. I'm Robert Krylowich, this is Radiolab. And so wait, what was the answer to my question about how does the fungus get the minerals?

[Robert Krulwich]

Oh, it's a three pronged answer. What a fungus does is it hunts, it mines, it fishes and it strangles.

[Sponsor Voice]

What?

[Suzanne Simard]

How the hell.

[Robert Krulwich]

I'm not making this up. In 1997, a couple of scientists wrote a paper which describes how fungi have.

[Jennifer Fraser]

Developed a system for mining.

[Robert Krulwich]

Jennifer says that what the tubes do is they worm their way back and forth through the soil until they bump.

[Jennifer Fraser]

Into some pebbles, these little soil particles.

[Robert Krulwich]

Packets of minerals, and then they secrete.

[Jennifer Fraser]

Acid and these acids come out and they start to dissolve the rock. It's like they're drilling and the fungus actually builds a tunnel inside the rock and it can, you can reach these little packets of minerals and mine them.

[Jad Abumrad]

What?

[Jennifer Fraser]

If you look at these particles under the microscope, you can see the little tunnels, they curve, sometimes they branch. They look just like mining tunnels.

[Robert Krulwich]

This is very like if you had a little helmet with a light on it. Like a human.

[Jennifer Fraser]

Yeah, maybe not with a helmet, but.

[Guest/Additional Commentator]

Yeah, it's like Snow White in the seven tubes or something.

[Robert Krulwich]

Wow. And that's just the beginning. Jennifer Todletov and I about another role that these fungi play, and that's hunter.

[Guest/Additional Commentator]

Hunter. Mm.

[Robert Krulwich]

What do you mean, like the plant is hunting?

[Jad Abumrad]

Oh, hunting.

[Robert Krulwich]

Hunter for water. I mean, the fungus is hunting?

[Jennifer Fraser]

No, no, no, the fungus is hunting.

[Guest/Additional Commentator]

The fungus hunter.

[Robert Krulwich]

How do you mean? How do you mean?

[Jennifer Fraser]

So they're the little insects that lives in the soil, these just adorable little creatures called springtails.

[Robert Krulwich]

They're sort of flea sized and they spend lots of time munching leaves on the forest floor.

[Jennifer Fraser]

They're called springtails because a lot of them have a little organ on the back that they actually can kind of like deploy and suddenly, boing. They spring way up high in the air.

[Robert Krulwich]

In the David Attenborough version, if you want to look on YouTube, he actually takes a nail, this pin will give you an idea, and pokes it at this little springtail. And the springtail goes. And you don't see it anywhere. It's gone into the air. Then of course, because it's the BBC, they take a picture of it. It's doing like a triple double axle backflip or something into the sky. It's the equivalent of a human being jumping over the Eiffel tower.

[Jennifer Fraser]

Anyhow, one of the things they eat is fungus.

[Robert Krulwich]

But then scientists did an experiment where they gave some springtails some fungus to eat. They sort of put them all together in a dish, and then they walked away. And then they came back and they.

[Jennifer Fraser]

Found that most of the springtails were dead.

[Robert Krulwich]

Instead of eating the fungus, it turns.

[Jennifer Fraser]

Out the fungus ate them in the little springtail bodies. There were little tubes growing inside them.

[Robert Krulwich]

What?

[Jennifer Fraser]

And this is what makes it even more gruesome. They somehow have a dye. And don't ask me how they know this or how they figured it out, but they have a little that they can put on the springtails to tell if they're alive or dead. When they did this, they saw that a lot of the springtails that had the tubes inside them were still alive.

[Guest/Additional Commentator]

Oh, that's cruel.

[Jennifer Fraser]

Yes.

[Robert Krulwich]

The fungus were literally sucking the nitrogen out of the springtails, and it was too late to get away. Nope, boink anymore.

[Jennifer Fraser]

And then they did experiments with the same fungus that I'm telling you about that was capturing the springtails, and they hooked it up to a tree to.

[Robert Krulwich]

Try to calculate how much springtail nitrogen is traveling back to the tree.

[Jennifer Fraser]

Well, 25% of it ended up in the trees.

[Robert Krulwich]

So they figured out who paid for the murder, right? The trees did, yeah.

[Guest/Additional Commentator]

Is there anyone whose job it is to draw little chalk outlines around the springtail?

[Robert Krulwich]

Inspector tail is his name. He's the only springtail with a trench coat and a fedora. Yeah, I have even. I can go better than even that. They have found salmon in tree rings. As in the fish in the tree? In the tree? Well, in a way.

[Jad Abumrad]

How the hell.

[Robert Krulwich]

Apparently, bears park themselves in places and grab fish out of the water and then, you know, take a bite and then throw the carcass down on the ground. The fungi, you know, after it's rained and snowed and the carcass has seeped down into the soil a bit, the fungi then go and they drink the. The salmon carcass down and then send it off to the tree, and the tree has evidence of its salmon consumption. I was like, wow, that's insane. Salmon rings in trees. That's insane. Look. And beyond that, there are forests. There are trees that the scientists have found where up to 75% of the nitrogen in the tree turns out to be fish food.

[Jad Abumrad]

From just bears throwing fish on the ground.

[Robert Krulwich]

Yeah. So if you would take away the fish. The trees would be like, blitzed, hobbled.

[Jad Abumrad]

Really? Is it as dramatic in the opposite direction? Like, the fungus seem to be giving the trees a lot of minerals. From the tree's perspective, how much of their sugar are they giving to the fungus?

[Robert Krulwich]

Well, I asked Suzanne about that. Like 2% or 0.0000001%?

[Suzanne Simard]

No. Well, people have been measuring this in different forests and ecosystems around the world, and the estimate is anywhere from 20 to 80% will go into the ground.

[Robert Krulwich]

What?

[Suzanne Simard]

Yeah, 20 to 80% will go into the.

[Robert Krulwich]

Below sugar goes down to the mushroom.

[Suzanne Simard]

Team, into the roots, and then into the microbial community, which includes the mushroom team. Yeah.

[Robert Krulwich]

The point here is that the scale of this is so vast, and we didn't know this until very, very recently, you have a forest, you have mushrooms. Now, it turns out that they're networked, and together they're capable of doing things, of behaviors, forestrial behaviors that are deeply new. We're just learning about them now, and they're so interesting.

[Jennifer Fraser]

Just for example, let's say times are good. The tree has a lot of sugar. I don't really need it all right now. I'll put it down in my fungi. And then when times are hard, that fungi will give me my sugar back and I can start growing again.

[Robert Krulwich]

What do you mean the fungi will give me my sugar back?

[Guest/Additional Commentator]

It's like a savings account.

[Jennifer Fraser]

It is like a bank.

[Robert Krulwich]

She says we now know the trees give each other loans.

[Jennifer Fraser]

Oh, yeah. Back and forth, seasonally. They can also send warning signals through the fungus.

[Suzanne Simard]

Yeah. So we've done experiments, and other people in different labs around the world, they've been able to figure out that if a tree's injured.

[Robert Krulwich]

It'Ll cry out in a kind of chemical way.

[Suzanne Simard]

And those chemicals will then move through them. That and warn neighboring trees or seedlings.

[Jennifer Fraser]

That something bad is happening. I'm under attack.

[Suzanne Simard]

There's an enemy in the midst.

[Robert Krulwich]

So if a beetle were to invade the forest, the trees tell the next tree, over here come the Paul Revere sort of.

[Suzanne Simard]

Yes. That seems to be what happens.

[Robert Krulwich]

So you can see this is like a game of telephone. One tree goes, oh, and the next one goes, oh, and oh. And then they do stuff.

[Suzanne Simard]

They start producing chemicals that taste really bad.

[Robert Krulwich]

So the beetles don't want to eat them.

[Suzanne Simard]

We go, ugh, I don't want that.

[Robert Krulwich]

One of the spookiest examples of this Suzanne mentioned is an experiment that she and her team did where they discovered that if a forest is warming Up. Which is happening all over the world. Temperatures are rising. You have trees in this forest that are hurting. They don't do well in warm temperatures, and their needles turn all sickly yellow. They will send out a. Oh, no, this is not so good signal through the network.

[Suzanne Simard]

But also, the other important thing we figured out is that as those trees are injured and dying, they'll dump their carbon into their neighbors. So carbon will move from that dying tree, so its resources, its legacy, will move into the mycorrhizal network, into neighboring trees.

[Robert Krulwich]

Oh, so it says to the newer, the healthier trees, here's my food. Take it, it's yours.

[Jennifer Fraser]

Or it could be like, okay, I'm not doing so well, so I'm gonna hide this down here in my. My Celia.

[Jad Abumrad]

Okay.

[Robert Krulwich]

I don't know if you're a bank or if you're a. So it's not necessarily saying, give it to the new guy.

[Jennifer Fraser]

Well, we don't know. I mean, again, it's a tree. It doesn't mean.

[Robert Krulwich]

I know, I know. I'm just trying to say, make sure I understand. I realize that none of these conversations are actually spoken.

[Guest/Additional Commentator]

Give it to the new guy.

[Robert Krulwich]

Give it to the new. Well, that's what she's saying.

[Suzanne Simard]

Yes, yes.

[Robert Krulwich]

Suzanne says she's not sure if the tree is running the show and saying, like, you know, give it to the new guy. Or maybe it's the fungus under the ground. It's kind of like a broker and decides who gets what.

[Suzanne Simard]

You know, I don't completely understand.

[Robert Krulwich]

She says one of the weirdest parts of this, though, is when sick trees give up their food, the food doesn't usually go to their kids or even to trees of the same species. What the team found is the food ends up very often with trees that are new in the forest and better at surviving global warming. It's as if the individual trees were somehow thinking ahead to the needs of the whole forest.

[Suzanne Simard]

So we know that Douglas fir will take. A dying Douglas fir will send carbon to neighboring ponderosa pine. And so why is that? And I think that the whole forest. Then there's an intelligence there that's beyond just the species.

[Robert Krulwich]

Wait a second, wait a second. You just used a very interesting word.

[Suzanne Simard]

I know, Robert. I have. You know what? It's 10 o' clock and I have to go. It's getting so interesting, but I have to go.

[Robert Krulwich]

Unfortunately, right at that point, Suzanne basically ran off to another meeting, but.

[Suzanne Simard]

Hello? Suzanne speaking.

[Robert Krulwich]

Oh, there you are. Hi.

[Suzanne Simard]

Hi, Robert.

[Robert Krulwich]

Hi. We did catch up with her a few Weeks later when we last left off. I'm just saying you just said intelligence. Don't professors begin to start falling out of chairs when that word gets used? Regarding plants, yes.

[Suzanne Simard]

We don't normally ascribe intelligence to plants, and plants are not thought to have brains. But when we look at the below ground structure, it looks so much like a brain physically. And now that we're starting to understand how it works, we're going, wow, there's so many parallels.

[Jennifer Fraser]

I do find it magical. I think there is something like a nervous system in the forest because it's the same sort of large network of nodes sending signals to one another. It's almost as if the forest is acting as an organism itself. You know, they talk about how honeybee colonies are sort of superorganisms because each individual bee is sort of acting like it's a cell in a larger body. Once you understand that the trees are all connected to each other, they're all signaling each other, sending food and resources to each other. It has the feel, the flavor of something very.

[Suzanne Simard]

Special.

[Robert Krulwich]

Thanks to Dr. Teresa Ryan of the University of British Columbia Faculty of Forestry, to our interns, Tiffany Tam, Roy Howling at the New York Botanical, to Stevenson.

[Jad Abumrad]

Swanson there, and to Annie McEwen and Brenna Farrell, who both produce this piece.

[Robert Krulwich]

Thank you.

[Jad Abumrad]

All right, co it okay.

[Robert Krulwich]

It's time for us to go and lie down on the soft forest floor.

[Jad Abumrad]

Yeah. And hopefully not be liquefied by the fungus beneath us.

[Robert Krulwich]

Nice final thought. Bye, everybody.

[Jad Abumrad]

Bye.

[Robert Krulwich]

I'm Robert Krulwich.

[Jad Abumrad]

I'm Jad Abumrad. Thanks for listening.

[Jennifer Fraser]

Start of message.

[Robert Krulwich]

This is Roy Holling, researcher specializing in fungi at the New York Botanical Garden.

[Jennifer Fraser]

This is Jennifer Fraser, and I'm a freelance science writer and blogger of the Artful Amoeba at Scientific American.

[Robert Krulwich]

Radiolab is produced by Jad Abumrad.

[Jennifer Fraser]

By Jad Abumrad.

[Robert Krulwich]

Dylan Keefe is our director of sound design.

[Jennifer Fraser]

Soren Wheeler is senior editor.

[Robert Krulwich]

Jimmy York is our senior producer.

[Jennifer Fraser]

Our staff includes Simon Adler, Brenna Farrell.

[Robert Krulwich]

David Gebel, Matt Kielty, Robert Crowich, Annie McEwen, Andy Mills, Lateef Nassar, Melissa O'.

[Jennifer Fraser]

Donnell, Kelsey Padgett, Arianne Wack and Molly.

[Robert Krulwich]

Webster, with help from Alexandra Lee Young, Jackson Roach and Charu Sinha.

[Jennifer Fraser]

Our fact checkers are Eva Dasher and Michelle Harris. And remember, if you're a springtail, don't talk to strange mushrooms. Actually, that's good advice for anyone.

[Guest/Additional Commentator]

Thank you.

[Jad Abumrad]

Bye.

[Robert Krulwich]

End of message.