Forests on Forests
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Wait, you're listening to Radio Lab from WNYC. Because they were wondering when they were going to go to the moon, they wondered how much dust would be on the surface of the moon and they were worried that

I once wrote letters back and forth to Neil Armstrong. So one of the things he told me is it was like they really weren't at all sure how much dust there was on the moon and whether it was, you know, variable. So you'd be standing here. I'm Lulu. I'm Latif. This is Radiolab. And it would take your weight and then you'd walk three steps forward and you'd be up to your knees in it. And this, of course, is none other than Crowley, the crow.

Robert Krowich. Really? I don't know why you didn't walk around more. I mean, you went to another celestial body. Producer Annie McEwan called him up a few weeks back to talk not about the moon, actually, although with Robert, you never really know where your conversations are going to go. But they talked instead about a new kind of world that was discovered right here in the forests of planet Earth. Yeah.

Okay, we're at long last ready to begin. Okay, so one of the first things I ever did when I got to Radiolab was work on a show of yours called Tree to Shining Tree. I don't remember how long ago we did that. That was like three years ago or something? It was 2016. Isn't that wild? I know. And for those of you who haven't heard the episode, you should go listen. It's amazing. It's amazing.

Just a tiny recap here. It was all about the network that exists under the forest floor. There's this whole other world right beneath my feet. This network is this deeply complex interwoven mat of tree roots and these mushroom threads, these fungi, connecting all of these trees together and helping them share resources. About the forest that exists underneath the forest.

Here from that episode is ecologist Suzanne Simard. 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've identified these as kind of like hubs in the network. It's just this incredible communications network that, you know, people had no idea about in the past because we couldn't, didn't know how to look.

Anyway, that episode is awesome. We learn about all this magical stuff that is happening right beneath our feet in the forest. But for this episode, I wanted to call you because I recently learned about this new layer to the story. So in Tree to Shining Tree, we look down under the ground. Right. Where do you think we should look now?

Well, I guess I'd be inclined, if there was more news, I'd do more down. Okay. I think. Well, how about, okay, how about instead of looking down, we peer into a type of down that is in the up? Oh, okay. Okay.

And to take us there, forest royalty. I've read that you are known as the queen of the canopy. Is that true? Where did that come from? I have no idea where that came from. I've also been called the mother of the forest canopy. And now that I'm 67 years old, I think it's going to be sort of the dowager queen or...

or the grandmother of Farr's Canopy. - I think you should be the empress. - What about the empress? - This is ecologist Nalini Nadkarni, who, like a lot of kids, spent a large part of her childhood up in trees. - You know, you grab a branch, you put your leg over it, and suddenly you're up in the treetops. And for me, it was like kind of my place. I had this sort of chaotic, large family. You know, I'd come home from school with chores and homework, but the treetops of these eight maple trees that lined my parents' driveway were kind of my refuge.

She'd spend whole afternoons up there just sitting and wondering. I look at the leaves and I go like, why does this branch have much yellower leaves than that branch, which has orange leaves? Yes, that's a good question. And it's like, well, what is going on? What is this, branch independence? Or, you know, I'd watch squirrels jumping from one tree to another and just think, God, you know, where do they go? And what

What if I attached a spool of thread to the back of one of them and I could trace where they go? But it was a place for my imagination to sort of run wild. Nalini grew up and followed that imagination to study ecology in grad school. This was back in like the early 1980s. And I was just starting out and I came to my...

graduate committee and said, "I know what I want to do with the rest of my career. I want to study the forest canopy." And they said, "Well, that's kind of like Tarzan and Jane stuff, you know, with so many questions to ask and answer on the forest floor. Why do you have to go into the canopy?" At the time, canopies were just basically not studied. They were hard to get up into and there didn't seem to be a lot of point. The scientific thinking was, there's just not a lot going on up there. But there was something about the canopy that I kind of just had this intuition.

that it's not enough to just stand on the ground and look up. And so, with some modified mountain climbing equipment, she began to climb these giant old-growth trees in the Olympic rainforests of western Washington. Which is what's called a temperate rainforest. Are these the places where in the morning the fog from the Pacific Ocean comes rolling in? Yeah. And the tree just gets an every-morning bath of just pure moisture? Yeah, and the tree just goes...

Yeah. So Nalini climbs up into the canopy of this giant big leaf maple tree. And I throw my leg over a branch and I'm sitting up there and I'm anchored with my rope and I'm looking around. I just see this...

enormous three-dimensional panoply of moving leaves and moving twigs. The branch she's sitting on, as well as all the branches surrounding her, are covered in this super thick layer of this amazing growth of mosses and lichens and ferns. Kind of like the tree is wearing this very unruly green shade carpet. You get the sense of being in a place that looks very simple from the forest floor, but is actually this kaleidoscope of life.

Her job up there was to take samples of the moss that was growing on these branches. I had to cut off chunks of it. So using some clippers, she begins to cut down into that moss on the branch she's sitting on. And as I peeled back those mats of mosses. Beneath, instead of just bare branch. I saw that there was all this soil up there. This branch has a foot of soil piled up on it. Oh, wow.

Soil that formed over many, many years of mosses and leaves dying and decomposing right there on the branch. It's so weird because you're sitting up there in the canopy like 100 feet above the ground and then you're digging your fingers into the soil that could be the soil that's, you know,

In your backyard garden, for goodness sake. You can imagine getting your gardening gloves out and planting rows of tulips a hundred feet in the air. There were like invertebrates in it. There were earthworms in it. Tree worms? Yes. That is so weird. I know, I know. Even the stars of the old episode, the fungi, were there. Really? So the mushrooms have climbed up the tree as well to sort of do their thing. They're sharing resources. They're helping the tiny plants up there communicate with one another. The same as on the forest floor. It's almost like she stumbled into a perfect

miniature of the forest floor she had just climbed up away from. And straddling a branch way up high in the air, she's like, huh, well that's cool.

This was in the 80s, and since then, there have been so many more, well, that's cool, because more and more scientists have been accessing this new world using cranes and ropes or building platforms. Or my favorite way up into a tree is this French guy, Francis Allais, who pioneered the use of the dirigible to access the canopy. Oh, wow. There's incredible pictures of these. So it's a balloon trip?

It's a balloon that floats over the tops of this green ocean, just kissing the tops of the trees, and the scientists can just gently lean and trim this and that. Anyway, so one way or another, all over the world, scientists began getting themselves up into trees and documenting what they saw there. And some of the coolest discoveries were found on the west coast in the old-growth redwood forests.

And oh my gosh, these giants were found to be holding these pockets of soil up to three feet deep. And growing in the soil were flowers, berry bushes, mosses, lichens. They found salamanders living hundreds of feet in the air who spend their entire lives never touching the ground. I'm waiting if you say a small deer or something like that, or something very weird. I mean, I don't have

smell dear for you, but I do have something that I find totally bizarre, which is that

Up in Redwoods, scientists have found these tiny aquatic creatures. An aquatic creature? It's aquatic, yeah. It's like the shrimp-like... They found a fish? Pretty much. It's like the shrimp-like thing, a species of something called a copepod. Copepods, which is actually this whole subclass of creatures. They're the most abundant animal in the ocean and a huge part of the diet of baleen whales. Ha ha ha ha!

This thing is like swimming around in these mossy mats and no one knows how it got there. Anyway, these tree canopies that up until the mid 80s, everyone thought were just pretty much empty. Not only are they not empty, they actually hold about 50% of all terrestrial life.

Did you say 50%? 50-5-0. Yeah. Wow, that's a weird number. You're saying 50% of it is up in the air somewhere? Yeah, up in the air, up in trees. Whoa. Which sounds kind of unbelievable, but when you think of places like the Amazon, all those bugs, birds, plants, animals, it adds up. And most of this life has made a home in these canopy soils. What? Soil on the tree branches?

And when ecologist Karina Mifune learned about these canopy soils... I fell in love. I was like, okay, there's like a forest in a forest on a forest. I need to research this. And she told me that thinking about these canopy soils like these tiny, perfect replicas of the forest floor below wasn't quite right. Because these canopy soils, they have something that the forest wants. ♪

Huh. Well, what would that be? Well, back when she was a grad student in the Washington Olympic Peninsula, Karina collected soil samples from the forest floor throughout the year. And she noticed that in the spring growing season, there aren't as many nutrients available. Specifically, there was a lack of phosphorus and nitrogen, two important things that every plant in the springtime wants to

to help them, you know, put forth new leaves, to help them grow. And those are rare. Plants love that. Right. Yeah. And in contrast to the last episode, where we talked about trees cooperating with each other. All these trees, all these trees that were of totally different species, were sharing their food underground. Like, if you put... Karina told me that in that same sharing forest, when resources are scarce... There's a ton of competition on the forest for trees.

Trees have roots grafted together. There's mycorrhizal networks, you know, that are spanning across. There's this big battle to, you know, uptake nutrients. But Karina had also taken samples of the canopy soils. And she saw that during these times of scarcity below... These canopy soils had so much more nitrogen and phosphorus available for plant uptake compared to their forest floor counterparts. Meaning that this soil for a plant...

was creme de la creme. It's just amazing. Downstairs, there's shortage. Upstairs, there's abundance. When it's crumbs down below, up in the sky, held aloft above the plebeian masses, is like a Thanksgiving dinner. And when Karina learned this, she thought, I don't know. What do these canopy soils mean? Because they're not just hanging out there. They're not just there for no reason, right?

She's right. They're not. These sky gardens, they get even better. Better at what? Hmm? Better at what? Well, let's just say they're not alone up there. What's about to happen? Well, I'm going to tell you. All righty. Right after this short break. Lulu. Latif. Radiolab. Back to Annie and Robert, where we were just about to learn the true superpower of...

Right. So to understand this wizardry, we need to go back to Nalini. Fine with me. And this amazing discovery that she made. Okay. So I remember sitting on this tree. She's back up in a tree in the Washington rainforest, digging around in this canopy soil. And I began seeing these root systems that were running up and down the branches of these trees. They didn't look like they belonged to moss or ferns or any other plant you could see up there. And there were fine roots.

Yeah, exactly. Exactly.

She gently excavates this root, scooting along the branch as she uncovers it. I was tied in so I could sort of swing around and move from one branch to another. I had my water bottle with me, so then whenever it began difficult to sort of unstick the root, I could just throw a little water on it, keep going, keep following it.

It was like, I don't know, it was like being a detective. But what did you think it was going to lead to? I had no idea. I thought, well, maybe there's some sort of vascular plant that I'm not aware of that's here, but I don't think so. So then she follows the route all the way back to its beginning. And oh my gosh, its origin was a dead end in the tree itself.

The big tree, the one Nalini is sitting in, is growing roots from its branch and snaking underneath these mats of soil, of canopy soil. Let me think about this. Somehow it realizes that it could find soil high up somewhere. And so it just takes its roots and its roots travel up and go whoop to the left and say, let's root not only where we normally root down there, but let's root up here. Yes. Whoa. Whoa.

So things that you thought were below can move above, way above, high above you. Yes. It was a real revelation. And Karina thinks that it's during a drought or during spring growing season when resources on the forest floor are scarce, that these big trees... That's when they can tap into their canopy soils. It's like, they're like, hey, there's a bunch of really great stuff here to suck on, so why don't you put out a root out here? And that's exactly what these trees do.

I kind of always compare it to like a secret cabinet that has all the good snacks in it. It's like if you were teaching a preschool, it's like while all of the school children are fighting over the snacks and fighting over these resources, you just go into your, you know, canopy soil closet and you got your good snacks up there. Because we're looking for those special minerals like the phosphorus and stuff, and that's where we can find it. Right. And it's finding it in its hat. Right.

You're finding it in its hat. That's a nice way of putting it. Yes. That's a lovely way of putting it. The expression, I'm going to eat my hat, has now got a whole new meaning. Oh, yes, Robert. I love that.

One thing that both Karina and Nalini told me is that this is a new field. There is just so many things to be found high above the forest floor. Like, for instance, Karina told me sometimes there are actual trees growing up there. And I've seen like a five-foot spruce growing out of a nook of canopy soil. Wow. And you'll see a lot of like baby maples growing up in the old maple. So it's like, you know, like a little nursery. Wait a second. You mean there's a tree growing on the tree? That's right.

On the branch? In the soil on the branch. Oh. And who knows? Maybe as more people study the canopy, we'll find little trees on those trees. And maybe there will be little trees on those trees on those trees. Yeah. It's fractal, like littler plants off the ground, and then little on them is the moss, which is little plants on top of little plants. So there's little layers and layers and layers of life. And the more you go up, the more the layers you will find. That's sort of cool.

Thank you, Annie McEwen, for reporting and producing that gorgeous episode and leaving us with that image of not turtles all the way down, but trees all the way up. This episode was reported and produced by Annie McEwen. Special thanks to Kiyomi Taguchi, Michelle Ma, and Nina Ernest. If you're interested in learning more about the story of Annie McEwen,

A huge thank you to Michael Werner and Joe Hanson and the team at PBS Overview. They tipped us off about Karina's research. They were the ones who got us excited about canopy soil in the first place. You can actually see all that gorgeous shag carpeting in the forest in their beautiful video, vivid color.

The video features Karina and other people who have dedicated their lives to saving what's left of the old growth forest. You can check that out on our website or on theirs. So thank you to them. And special thanks, of course, to the many ringed tree trunk that is Robert Krolwich coming back on the show to talk trees with us. Thank you for doing that, Robert. We love you. That guy's all bark, no bite. You know what I mean? That's why I like him.

All right, Latif, before we go, go, go for real, real, real. Right. For folks who maybe enjoyed this story of a mystery tree, I thought they might also enjoy to know that there is a new series coming out about a mystery meat. The mystery meat.

Spam. So I just want to take a quick moment here to let you know that our friends over at The Experiment have just dropped a three-part series on spam. Oh, it's the thing I've been craving without even knowing that I was craving. I love it.

I wasn't. I actually had quite an aversion initially when they told me they were working on this. Not a spam fan over here, but I am a fan of what the experiment people are up to. So it turns out the reporter and producer Gabrielle Burbey went on this journey to kind of uncover why her grandpa, who grew up in the Philippines, had such an attachment to spam. She thought it'd be a cute little one-off episode of

And at the beginning, she ends up taking this kind of wondrous Willy Wonka tour through the Spam Museum, which is down the road from the Spam Factory. And she ends up encountering all these institutionalized spam puns, which I think you'll really enjoy. And just to give you a preview, just play you a quick bit of that. I'm the Spam Manager. Savile Lord, the Spam Manager. So everything with Spam we make, we have fun with.

We have spambassadors who help us here out at the museum. We have about 20 of them. And then I'm the spam manager. And then we really encourage people when they leave the museum to have a spamtastic day. We serve spamples, which are just a little piece of spam on it with a pretzel.

But the more and more she got into her reporting, this thing kept coming up about a strike. A strike at the spam factory that kind of changed not just the course of this town, but sort of the labor movement in America. And the more she tried to get people to talk about it, no one would talk. So when I say...

People don't talk about the strike. I mean, like, to this day, they don't talk about the strike. The strike tore this town apart.

Families and friendships were torn apart. This is a dark stain on the town. It was horrible. You can feel the trauma of this strike. It didn't destroy Austin, but it did change it forever.

It is part of the creation myth of that town. You know, if there's a defining moment for the town, it's this. Everybody's got something ugly in their past that defines them, whether we want it to or not. And there are a lot of things you can say about Batman, but at some point you're going to have to talk about the Joker. And I don't think you can talk about Austin without talking about the Joker, which is this strike.

And anyway, it is a surprisingly beautiful and weirdly relevant series. So we just wanted to give folks a little preview and let them know to go check it out on the experiment. It's called Spam, How the American Dream Got Canned. Got canned. Okay, let's, yeah. I, for one, I'm excited to unroll the tin.

and see what's in there. Okay, great. Okay. Go check it out. You can find it on The Experiment, wherever you get podcasts. Spam, how the American dream got canned. Spam, how the American dream got canned.

Radio Lab was created by Jada Boomrod and is edited by Soren Wheeler. Lulu Miller and Latif Nasser are our co-hosts. Suzy Lechtenberg is our executive producer. Dylan Keefe is our director of sound design. Our staff includes Simon Adler, Jeremy Bloom, Becca Bressler,

With help from Carolyn McCusker and Sarah Sonbach. Our fact checkers are Diane Kelly, Emily Krieger, and Adam Schibble.

This is Amanda Darby calling from Rockville, Maryland. 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 Sloan at www.sloan.org. Science Reporting on Radiolab is supported in part by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science.