Forests on Forests

From Trida Shining Tree, which was about these vast networks hidden in the forest floor.

“- She began thinking about the forest that exists underneath the forest. - That's Robert Krollwich, who was one of our host at the time.”

If you haven't heard the episode, you really should. We profiled this scientist Suzanne Samard, who discovered to even her own great surprise, these deeply complex interwoven mats of tree roots and mushroom threads, connecting trees together, helping them communicate, even share resources. Like, there's a literal underground economy in every forest you've ever been to. - Turns out one tree was connected to 47 other trees all around it. It was like a huge network.

The trees that were the biggest in the oldest were the most highly connected. 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. - So that was back in 2016. A couple of years after that, the producer of that episode, Annie McEwen, brought to us another story that shocked us all over again, because we realized that whole forest floor thing, that was just half of the story. So, in celebration of spring and all the things growing around us right now, we wanted to replay that episode about the other half of the story of what's going on in forests. And to do so, of course, that perfect pairing of producer Annie McEwen and Emeritus, Radio Lab host, Robert Krollwich.

- Okay, we're ready. You're out too long last really to begin. - Okay, so for this episode, I wanted to call you because I recently learned about this new layer to the story. - Okay.

- So, in tree to shining tree, we looked 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. - Well, how about, okay, how about instead of looking down, we peer into a type of down that is in the up. - Oh, okay.

- And to take us there, already, forest royalty. I've read that you are known as the Queen of the Canopy. - Is that true? - Is that true? - Where did that come from?

- I have no idea where that came from.

“- Well, it's called the Mother of the Forest Campus, and now that I'm 67 years old, I think it's going to be sort of the Dowager Queen or the Grandmother of the Forest Campus.”

- What about the end? - This is ecologist Malini 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 tree tops. 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 tree tops of these eight maple trees that lined my parents driveway were kind of my refuge. She'd spend whole afternoon up there, just sitting and wondering, and look at the leaves, and I go like, "Why is this branch have much yellow or leaves? Then that branch, which has orange. - That's a good question!" - And it's like, "Well, what is going on? Why? What is this branch independence?"

You know, I'd watch squirrels jumping from one tree to another and just think, "God, you know, where do they go?" And what if I attacked the spool of thread to the back of one of them, and I could trace where they go? So, but it was a place for my imagination to sort of run wild. - Millini 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 I 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 or why do you have to go into the canopy.”

- At that 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. - These are the places where in the morning the fog from the Pacific Ocean comes rolling in.

- Yeah, the tree just goes, yeah. - So, Millini 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 like ends 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 of 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 being to cut down into that moss on the branch she's sitting on.

- And as I peel back those mats of mosses beneath instead of just bare branch, I saw that there was all the soil up there. - This branch has a foot of soil piled up on it. - Oh well.

- 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 a hundred 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 the forgiveness sake. - You can imagine getting your gardening gloves out and planting rows of tulips. - A hundred feet in the air.

“- They were like invertebrates in it, there were earthworms and a tree worms?”

- Yes, but it's 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. - Yes, 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 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 old that's cool.

Because more and more scientists have been accessing this new world using cranes and robes or building platforms or my favorite way up into a tree is this French guy, Francis L.A. who pioneered the use of the dergable to access the canopy. - So it's a balloon? - 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 of 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 Forest. And oh my gosh, these giants were found to be holding these pockets of soil up to three feet deep. And growing in this soil were flowers, berry bushes, mosses, likenes.

They found salamanders living hundreds of feet in the air who spend their entire lives never touching the ground.

- I mean, I mean, I don't have a small deer for you, but I do have something that I find totally bizarre, which is that up in Redwood's scientists have found these tiny aquatic creatures.

“- An aquatic? - It's aquatic, yeah, it's like the shrimp lake. - They found a fish?”

- Pretty much it's like the shrimp flesh thing, a species of something called the copapaz, 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 bailing whales. This thing is like swimming around in these mossy mats, and no one knows how to got there. - Anyway, these tree canopies that up into 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 on the planet.

- Do you see that? - 50%? - 50? - 50? - Yeah. - Wow, that's a weird note. You're saying 50% of it is up in the air? - Yeah, up in the air, up in trees, 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 a collegeist Karina Mfune learned about these canopy soils? - I fell in love. I was like, okay, there's a forest in a forest on a forest.

I need to research this. - And you 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.

Karina collected soil samples from the forest floor throughout the year.

- And she noticed that in the spring growing season, there are as many nutrients available.

“- Specifically, there was a lack of phosphorus and nitrogen, two important things that every plant in the springtime wants”

to help them 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 floor trees, have roots grafted together.

There's micro-risal 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 forestwork counterparts. - Meaning that this soil for a plant was crem-delacrem.

- It's just amazing. - Downstairs, there's shortage. Upstairs, there's abundance.

- When it's crumbs down below, up in the sky held a loft above the pluvian 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 a reason, right? - She's right, they're not. These skyguards and they get even better. - Better at what? - Better at what? - Well, let's just say they're not alone up there. - Let's about to happen. - I'm going to tell you. - Alrighty. - Right after this short break.

- Each story you hear on planet money starts with a question. What happens if we refund tariffs? Why are grocery so expensive? - And NPR, we stand for your right to be curious, because the forces shaping our world can be hard to see. Follow NPR's planet money wherever you get your podcasts and start seeing how the economy really works. - Really? - Let their radio lab back to Annie and Robert, where we were just about to learn the true superpower of those gardens in the sky.

- Right, so to understand this wizardry, we need to go back to Nilemi. - 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 they were fine roots all the way up to some of them were the diameter of my wrist. I mean, these were gigantic roots.

“- What? - And I thought, well, that's weird. What are these roots doing here?”

- So I began just tracing the roots that I was finding. - Like you took hold of one written your hand instead of like wet black words like a string. - Exactly like it's like following a string, exactly. - She gently excavates this root, scooting along the branch as she covers 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 was 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. - Well, what do you think it was going to lead to? - I had no idea. Well, maybe there's some sort of vascular plant that I'm not aware of that's here, but I don't think so.

- Wow. - So then she follows the root all the way back to its beginning. And oh my gosh, it's origin was a dead end in the tree itself. - What? - The big tree, the one lenient 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 until it just takes its roots and it's roots travel up and go up to the left, to say let's root not only where we normally root down there, but let's root up here. - Yes. - Oh. - So things that you thought were below can move above, way above, high above you. - Yes.

- And create a thinks that it's during a drought or during spring growing season when resources from 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're 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 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 what we can find it.”

- Right, and it's finding it in its hat. - In finding it in its hat. That's a nice little way of putting it. - Yeah. - That's a lovely way of putting it. The expression I'm going to eat my hat has not got a whole new feeling. - Yes, Robert, I love that.

- One thing that both Karina and Nileenie told me is that this is a new field. - There is so many things to be found, a high above the forest floor. - For instance, Karina told me sometimes there are actual trees growing up there.

- It's seen a five-foot spruce growing out of a nook canopy soil.

- Wow. - You'll see a lot of baby mables growing up in the old maple, so it's like you know, like a little nursery. - Please, I 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. - It's practical, like little plants off the ground. Then little on the ground is the moss, which is little plants on top of little plants.

So there's little layers and layers of life.

And the more you go up, the more the layers you'll 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 Yomi Taguchi, Michelle Ma, and Nina Ernest. - A huge thank you to Michael Warner and Joe Hanson and the team at PBS Overview. They tipped us off about Kermina's research. They were the ones who got us excited about the canopy.

“So in the first place, you can actually see all that gorgeous gag carpeting in the forest.”

In their beautiful video, vivid color. The video features Kermina and other people who have dedicated their lives to saving what's left of the old growth forests. You can check that out on our website or on the airs. So thank you to them.

And special thanks, of course, to the many ringed tree trunk that is Robert Crowwich. 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. That's all for us. Catch you next week.

Hi, I'm Gabby. I'm from the Bay Area California and here are the staff credits. Radio Lab is hosted by Lulu Miller and Latif Nasser. Soren Wheeler is our executive editor. Sarah Sandback is our executive director.

Our managing editor is Pat Walters. Dylan Keefe is our director of Sound Design. Our staff includes Jeremy Bloom, W Harry Fortuna, David Gable, Maria Paz Gutierrez, Sündu Nina Sambandon, Matt Kilti, Mona Murgauker, Annie McEwen, Alex Nison, Sara Kari, Natalia Ramirez, Rebecca Rand, Anise Vizza, Arian Wack, Molly Webster and Jessica Young,

with help from Gabby Santas. Our fact checkers are Diane Kelly, Emily Krieger, Natalie Middleton, Angelie Mercado, and Sophie Samayi. Hi, I'm Aubrey, calling from Salt Lake City, Utah. Leadership support for Radio Lab Science Programming is provided by the Simon Foundation and

the John Templeton Foundation. Foundation support for Radio Lab was provided by the Alfred P Sloan Foundation.

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