Science Friday - Mammoth Pool Fire, Fun Squirrel Facts, Soil Importance. Nov 12 2021, Part 2

Episode Date: November 12, 2021

As Wildfire Intensity Rises, So Does The Human Toll Of Blazes It was Labor Day 2020, and Mammoth Pool Reservoir, in California’s Sierra Nevada, was buzzing with campers. Karla Carcamo and her parents, siblings, cousins, and countless others, mostly from the Los Angeles area, have been coming here every Labor Day for 17 years. “Most of it is my family, and family that’s invited family, and those family friends have invited friends of theirs,” she says. “I’m telling you, we have over 200 people.” Alex Tettamanti and her husband Raul Reyes are also Labor Day regulars. Every year, they drive in from Las Vegas to meet up with an off-roading club made up of a few dozen families from across the West. They fill their weekend with jet-skiing, ATVing and hiking. “It’s beautiful,” says Tettamanti. “The smell of all the pine trees and stuff, and the trees are so big, it’s really cool. The campground and reservoir are nestled at an elevation of about 3,000 feet in the Central California foothills a few hours northeast of Fresno. The attraction is unfiltered Sierra Nevada: Sparkling blue water surrounded by a thick forest of stately ponderosa pines and black oaks. Plus, it’s isolated. There’s only one road in and out, which dead ends at the lake. “Being there, let me tell you, it’s like a little piece of paradise,” says Carcamo. That Friday passed like any other. Groups split up to go hiking, swimming and grilling, and Carcamo’s family prepared for their annual pupusa night later in the weekend. By Saturday morning, however, the atmosphere had changed. “When I woke up, I did notice it was kind of cloudy,” says Reyes. “The sky was orange and there was ash, like big pieces of ash falling,” says Reyes’ friend Vicky Castro. Read the rest at sciencefriday.com.   Squirrel-Nut Economics And Other Agility Tricks In many parts of the country, the lead-up to winter is a busy time for squirrels, furiously collecting and hiding acorns and nuts for the cold months ahead. But how can squirrels recall where it has stashed all its stores? And what can studying squirrels tell researchers about memory, learning, and economic decision-making in other species? Ira talks with Lucia Jacobs, a professor in the department of psychology and the Institute of Neuroscience at UC Berkeley, about her studies of the campus squirrels—from learning about their cognition, learning, and memory to recording the acrobatic movements of a squirrel on the ground and in the treetops. Jacobs co-leads a "squirrel school," observing rescued and orphaned juvenile squirrels as they learn normal squirrel behavior, and is contributing to a project seeking to develop robots using agility tricks learned from the rodents.   What Will We Reap Without Topsoil? You may have missed the research when it came out this February: a paper in the Proceedings of the National Academies of Science reporting on satellite studies of farmland topsoil in the nation’s corn belt, states like Iowa, Indiana, and Illinois. And the news was not good. The team estimated that more than one-third of the topsoil in this region is gone, eroded mostly from hilltops and ridgelines, thanks to the plowing and tilling processes used to perform industrial agriculture. That topsoil, some of the richest in the world, is carbon-rich and crucial to our food supply. And yet it’s continuing to wash away, a hundred years after scientists like Aldo Leopold first called out the threat of erosion. This erosion, as well as other degradation of soil’s complex structure and microbiome, continues at a fast clip around the globe, hurting food production and ecosystems health. In addition, soil could be helping us contain more than 100 billion additional tons of carbon dioxide from the atmosphere—if we let it. But the good news, according to University of Wisconsin soil scientist Jo Handelsman, is that the solutions like cover crops and no-till farming are simple, well-understood, and easy to implement—as long as we give farmers incentives to make the leap. She talks to Ira about her forthcoming book, A World Without Soil: The Past, Present, and Precarious Future of the Earth Beneath Our Feet. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. In the West, a number of factors, including climate change, have turned fire season into a nearly year-round affair. Wildfires used to ignite mostly in the summer and fall. But now it's all too common to see them touch off in the springtime and smolder all the way through to the following winter. And as temperatures rise, these fires have become larger, longer, and more destructive. More fires has meant more property damage, loss of forest ecosystems. It has also meant more people trapped in dangerous situations. Last year, during the so-called Creek Fire in California, Sierra Nevada Mountains, emergency responders were put to the test in one of the most dramatic rescues in recent history. Nearly 250 campers had to be airlifted out of the backcountry where they'd been vacationing over a holiday weekend. It's a powerful and

disturbing story, and it was chronicled in a podcast by reporter Kerry Klein of Valley Public Radio in Fresno, California. 911, the emergency. How do you respond under pressure? We're at Wagner's campground, and it seems like there's a fire south by where the lake is. When you find yourself in an unimaginable situation. Which lake are you at, sir? No, man is pool lake.

Do you stay calm? Do you see flames from where you're? are right now? Every, in every direction, yes. Focused? How many, approximately how many people are down there, approximately? I want to say 150 to 200 people. But we have burned, burn victims, and we have a girl that severely burn. When does that tough veneer start to give way? We are literally, we have people running to the lake, like on foot running to the lake as fast as they can because there's fire everywhere. To fear. Fire on both sides of the truck.

There's a word driving through the fire. And panic. And what do you do when there's only one way to survive? Then you have to get out and you have to run to the lake. Just get in the water and that's the best you're going to be able to do, okay? Wow, those are really powerful to listen to. Those voices are from 911 calls made that day and rest assured, everyone made it out a lot. The podcast is called Escape from Mammoth Pool, and it examines the factors that have contributed to a worsening wildfire season and the growing toll on people across the West.

Based on her reporting for that series, Kerry Klein produced the following story exclusively for Science Friday. It was Labor Day weekend 2020, and Mammoth Pool Reservoir was buzzing with lots and lots of people, like Carla Karkamo, whose family has been coming here for 17 years. Most of it is my family. and family that's invited family. And those family friends have invited friends of theirs. I'm telling you, we have over 200 people. Alex Tenamante and her husband Raoul Reyes are also Labor Day regulars. They come in from Las Vegas, along with a few dozen other families in an off-roading club.

They go jet skiing, ATVing, and hiking. It's beautiful. Just the smell, I mean, everything. Yeah, just the smell of all the pine trees and stuff. And the trees are so big. It's really cool. The campground and lake are nestled at an elevation of about 3,000 feet in the foothills of central California, a few hours northeast of Fresno. The draw is unfiltered Sierra Nevada, sparkling blue water and stately ponderosa pines and black oaks. And it's isolated, only one road in and out.

Being there, let me tell you, it's like a little piece of paradise. That Friday passed like any other. Hiking, swimming, grilling. Carla's family got ready for Papusa night later in the weekend. But by Saturday morning, the atmosphere had changed. Raoul and Alex noticed it and their friend Vicky Castro. So when I woke up, I did notice it was kind of cloudy. The sun was kind of like orange color.

The sky was orange and there was ash, like big pieces of asphalt. They were seeing smoke from a small fire that it ignited just the night before. The blaze would become the crime. creek fire, which went down as one of the largest in state history. But at that time, it shouldn't have been a worry. At breakfast, it was just a few hundred acres in size and close to 10 miles away. The folks at the general store weren't concerned, and neither were the people fishing at the dam. But that didn't keep Alex from making a dark joke over her birthday mimosis. I said, if there's anything here that you think is important, you better take pictures of it for insurance before you go on this hike. Looking back at it,

I can't believe that it came out of my mouth. The joke proved to be prophetic. Within a few hours, the fire would grow from just 600 acres to more than 45,000. It overtook the campground. Flames and fallen trees blocked the one road back to civilization, forcing campers to flee in the other direction to the relative safety of the lake. And that's when 911 calls came pouring in. The lake was only two miles away, but the drive was agonizing.

Hikers went missing. parents were separated from children, and panicking drivers had to dodge fallen trees and encroaching flames. Many campers, including Raul, told me that drive felt like an eternity. When you're in a situation where you think your life's going to end, it's everything's going to just slow down completely. Mercifully, low water levels at the lake meant people had space to park their vehicles on sandy lake bed between the water's edge and the trees. And they had gotten there just in time. Alex says shortly after most people arrived, the fire closed in, burning all the way to the tree line. She watched the flames approach from inside her Dodge pickup truck where she was blasting the air conditioning to keep the smoke at bay.

That's when it really felt like the true fire was coming through. You could feel and hear the wind whipping across the vehicle. You could hear and see the embers flying everywhere, hitting trucks and trailers and stuff like that and just like explode. Vicki and her family were among dozens of people who actually got into the water. They waded up to their chests and held up foam pads to fend off flying ashes and embers. Vicky says her kids and niece and nephew, all between six and 14 years old, were crying, petrified that they were about to die. And at that point, I was like, you know what, this is not where this is like, we're not done. That's not the way that all of us end up.

And she was right. After a few nail-biting hours, the thump-thump-thump of two military helicopters cut their way through the billowing smoke and whipping wind. It was the California Army National Guard. Everybody was screaming. Everybody basically started cheering. And they started saying, turn on all the lights so they know that we're down here. Car headlights, flashlights, cell phones. I mean, anything.

And just everyone was just screaming, yelling, honking. In a white-knuckled rescue operation that lasted a. into the early hours of the next morning. Two choppers airlifted 242 people stuck at the lake and 16 dogs back to Fresno. The seven crew members later received prestigious aviation awards personally from then President Donald Trump. And there were heroes among the campers too, people who had shuttled strangers to safety and search parties who had raced back into the smoldering forest to rescue hikers. Everyone survived that weekend, though some would be hospitalized and even need surgery

for burns and other injuries. They had all outrun one of the fastest moving wildfires in California's history. Here's Vicki Castro's husband, Rolando Rosales. When I tell the story to people, I just tell him, you know what, it was like a movie, but in real life. The rescue effort at Mammoth Pool Reservoir was an outlier. The creek fire went down as California's fourth largest blaze, and fire officials can recall a wildfire-related rescue even close to that size.

And yet the incident still treasurer. with a frightening trend that as the intensity of wildfire season increases, so too does its social toll and the risk to human life. We've seen the direct impact of the increase in fires and how that's having a direct impact to the people of California through loss of communities, through loss of industry, through, you know, simple fact of being evacuated for extended periods of time and disrupting people's, you know, day-to-day lives. That's Battalion Chief John Heggy, a firefighter and public information.

officer in San Diego with Cal Fire, the state agency responsible for battling blazes. It touches so many different areas that it'd be naive to say that it doesn't affect everyone in California to some extent. Wildfires in the West are evolving. More are burning each year. Calfire estimates wildfire season is now two and a half months longer than it was 50 years ago. And the annual acreage burned has hit a record four times in the last 15 years. Heggy says when he started fighting fires in the 90s, a big blaze would be 50,000 acres. That would take, you know, two, maybe three weeks to get that type of acreage consumption. Now we're doing it in a single 24-hour period. Case in points, the creek fire, which burned close to 50,000 acres the day it reached

mammoth pool. It would burn nearly 400,000 acres before being contained. The shift could be blamed on two main factors, says Mark Meyer, an ecologist with the U.S. Forest Service. First, there's too much fuel on the landscape, fuel being trees and other stuff living and dead that can feed the flames. And then there's climate change, which exacerbates extreme weather and likely contributed to the state's hottest drought on record last decade. You take either one of those and they're a pretty significant stress around the system. But you put them in together and they work almost synergistically to increase the scale, the intensity, the severity of our fires that we're seeing today. Throughout much of the West, fires burned pretty freely until around a century ago when we began suppressing them

to protect development in the so-called wild and urban interface. According to Julianne Stewart, a forester in the central Sierra, those forests had adapted to frequent burning. Those fires happening every five to ten years, there wasn't a lot of buildup of brush and understory. And so the fire was low intensity and it crept around on the ground and you got these very open forests that just kind of naturally maintained themselves. And so, After decades without regular fires, that landscape was primed for a megafire. Add drought to the mix, and that means more trees fighting for less water, had fewer defenses to fend off pests like bark beetles. By late 2019, more than a hundred million trees throughout the state's forests were estimated to have died.

That's just a huge amount of fuel on the landscape. So what does all this mean for people? In the last 20 years, the costs of firefighting have risen steadily. More buildings, more buildings, buildings are being destroyed. And in the last four years, wildfires killed 180 people in California. That's three times the total of the entire previous two decades. Here's Daniel Urius, a battalion chief with Cal Fire and the Fresno County Fire Department. Anyone in California knows that wildfires ravage the state consistently. It is having a toll on fire personnel and the general public. Understandably, a mental health crisis related to wildfires is emerging. A recent review of hundreds of research articles reveals higher rates

of anxiety, depression, and post-traumatic stress disorder among people affected by fires. Risk factors, of course, include losing a home or community to fire, but also the experience of evacuation and fearing for one's life and the feeling of a lack of support from the government. Uriah says mental health issues are also becoming apparent among firefighters who are stepping into ever-riskier situations. noticed that with our employee support services being called upon more frequently by our employees. Employees are, you know, looking for more time off when they do get back from these campaign fires just so they can get back to a sense of normalcy. Then there's the wildfire smoke, which used to be a short-term threat for nearby communities,

but is now lasting longer and drifting across the country. A recent data investigation by NPR's California Newsroom revealed that in some parts of the West, wildfires have quadrupled the number of hazardous smoky air days compared to just 10 years ago. The particulate matter in smoke has been associated with respiratory and cardiovascular issues, and data reporter Alison Saldana observed a spike in hospitalizations for heart and lung diseases during bad fire seasons. What we found was that California recorded 30,000 more hospitalizations in 2018, which was a particularly destructive fire oil compared to 2016 when there were less destructive fires. Exposure to particulate matter has also been associated with pregnancy complications and preterm birth,

and emerging research suggests there may be a link with decreased cognitive function among adults. Another question is whether people in the wilderness are now more at risk of getting caught up in wildfires and whether that could put search crews in danger too. That night at Mammoth Pool Reservoir, the rescue was nearly as harrowing for the National Guardsmen in the air as it was for campers on the ground. Here's Chief Warrant Officer Joseph Rosamond of the California Army National Guard, who piloted the larger of the two helicopters. The visibility immediately dropped from clear when you're on one side of the fire to almost zero when you're on the inside of the fire. For a moment, I was like, oh, man, this is really bad. of the flight conditions and the need to fill the choppers beyond capacity to get everyone out.

Rosamond says this mission went beyond flights he's taken even while on active duty overseas. I've done, you know, night air assaults into bad guy country and doing all this other stuff. I've been shot out. I've been all of it. But this was by far the most dangerous, most, yeah, risky thing that I've ever gotten myself into. So are rescues like this going to become more commonplace as fires become faster and more intense? It's something that worries Jack Haskell. He's a trail information manager with the Pacific Crest Trail Association, and he says in the last few years, he's seen a steady rise in calls from hikers seeing smoke. I could absolutely see emergency scenarios with these megafires that are growing really fast. And I know how busy

our public lands are, and I can absolutely see scenarios where hundreds of people are stuck. No single agency handles all the data on wildfire-related rescues in California. But as far as Sergeant Jeff Andrees can tell, rescues are still so rare that it's unclear if they're becoming more common. Andres is a helicopter pilot with the California Highway Patrol, which handles search and rescue for Cal Fire. Since 2017, he says, his helicopter team and Central California has responded to about 10 wildfire-related calls. A couple examples of that is we've had a couple of rescues of fire personnel, but we've had multiple calls where we have assisted with hikers up in the mountains who become lost

due to either the fires and the smoke itself or fire damage to the trails. He says agencies like his are equipped to also prevent emergencies. For instance, one of those calls was to a remote area of the Pacific Crest Trail. There was no cell service to warn hikers of a nearby fire, so helicopters flew in and used their PA system to broadcast evacuation orders. And Andrews says the closures earlier this fall of many of California's forests served to prevent both wildfires and injuries. It's proactive on their part to be shutting down the forest

to make sure there's less numbers of people that are going to be affected should the fire continue to spread or continue out of control. A year after the harrowing rescues at Mammoth Pole Reservoir, Carla Karkamo and the other survivors are doing okay. Raoul Reyes says he had nightmares for weeks afterward. Vicki Castro's son still shakes at any mention of fire. And many who were injured have actually sued Madera County for not notifying the campers the fire was approaching.

For others, the weekend served as a wake-up call to be smarter in the wilderness. Here's Rolando Rosales and Alex Tedamante. I will go again. My kids say the same thing, but we will be more careful. I will maybe plan an escape route or something. Yeah, we just don't mess around with fire no more. Like, if the sun is orange, I'm out of there. I don't care where I'm. I don't care if I'm in the city.

I don't care if I'm gone. I don't play no more. Hopefully, no one else will need to learn those lessons the same way they did. For Science Friday, I'm Carrie Klein. A great story. Carrie Klein is a reporter at Valley Public Radio in Fresno, California. Learn more about the podcast, Escape from Mammoth Pool. Go to sciencefriiday.com slash mammoth pool. After the break, scampering to answer questions about squirrels. Stay with us. This is Science Friday. I'm Iroflato. In many parts of the country were just past peak squirrel season, when the bushy-tailed rodents are in overdrive, hiding nuts for the winter ahead. And if you've ever spent time like I have, watching a squirrel hide a nut,

only to zoom away, run along a cable, or devise some acrobatic assault on your bird feeder, which I have watched too many times, you've probably got squirrel questions. Joining me now is Lucia Jacobs. She's a professor in the Department of Psychology and the Institute of Neuroscience at UC Berkeley, and she co-lead something called Squirrel School. Welcome to Science Friday, Dr. Jacobs. Is school in session now? Schools in session. Thanks for having me.

You're welcome because I have such mixed feelings about squirrels. Like I said, they attack my bird feeder, they dig up my bulbs, yet I am in admiration of them for their athletic and acrobatic abilities. They're unbelievable. Well, I think squirrels are very polarizing, and there are many people. people who would state what you just said much more strongly that they actually hate. We are on the radio, so I couldn't really tell you. Okay. No, it's fascinating. It seems some people are fascinated and walk to the park with bags of nuts and other people can't stand them.

And, you know, my response is squirrels are like humans. I mean, they're very similar. The Eastern Gray, we're talking about the Eastern Gray squirrel. They're extremely smart. They're extremely destructive. they're generalists. They can kind of eat most anything. At the same time, they're specialists because they have this fascinating co-evolved relationship with oaks and hickories so that because of them, we have for us. So people have a lot of mixed feelings, I think. Yeah. So tell me about your feelings. How did you get interested in squirrels in this whole universe of animals to study cognition in? Well, it was actually, it did come down to the food story. because I was fascinated that there are different squirrel species on the East Coast that store

food differently. And the red squirrel puts all its eggs in one basket and defends a basket, larder hoarding. And the eastern gray is obligate scatter hoarder, where every large seed is individually buried and without defense. And so I was fascinated by the kind of economics of these two species that often overlap, how did they work that out? So it's really interested in their kind of economic systems. And since then, I found it, that was a good place to start, because the Eastern Gray squirrel does, in fact, have a fascinating and complicated economic system. Well, when you say economic system, is that me making choices about burying the acorns or eating them or exactly what are you talking about? I don't think of squirrel economics, but I will now.

No, I think if you think about humans, you get some income and you have to decide, do I spend it now? Do I save it for the future? And that's what squirrels do also. That's why squirrels and humans are so similar. All these nuts come in. Do I eat the nut? Do I cash it? Do I cash it?

Where do I cash it? How do I protect it? How do I defend it? When do I get it back again? So squirrels have months and months of forging decisions about one. nut. And they have to do that about 3,000 times every, every year. So do they obsess over this? I mean, you know, you know, get crazy because they have to make all these decisions. What's fascinating is when we looked at these decisions in the summer, for squirrels, the summer is a

terrible time because they've eaten all their stores from the year before and the new crop hasn't showed up. And so the summer is when they're actually very thin, very starving. That's when they're really going to attack your bird feeders. And what we found is when you give squirrel's nuts in the summer, they make that decision much more slowly, much more carefully. We actually quantify a squirrel picks up a nut and they roll it in their paws and then they put it in their mouth and they shake their head from side to sides very quick. You have to look very carefully to see it.

And what we showed is they're actually weighing the nut. And depending on how much the nut weighs, they will carry. that nut a little further away from the place where they found it because the place where they found it is generally where all the other squirrels are and so they want to get it far away as possible. So it's this really careful economic decision and we can actually see them doing it because we can quantify these paw movements so you can actually see an animal thinking, what is this worth? And then you can see their response and there's all these different kind of ecological factors that go into this one little decision.

But in the fall, the fall is when they turn into cashing machines. That's when you've got all this availability, and the decisions are very fast. Do we have any idea, speaking of burying those nuts, of how they remember all those hiding places? I mean, we've shown with captive squirrels that they remember, and that's not a surprise. This is what we've been able to show in the lab is the, that they're very accurate. And when they're very hungry, they go first to their own caches and then they go to other squirrels' caches.

Because squirrels have a very good sense of smell. And they, in fact, if you plant 80 walnuts in your backyard, a squirrel will come and find 79 of them within a month. But the way we've interpreted this, as you can see when they're very hungry, they go first to the sure thing. I mean, you would do the same thing. If you're starving, you're not going to cook an elaborate meal.

You're going to grab something right on the counter, right? And that's what the squirrels do. But if you think about squirrels, the natural conditions, they're living in areas with snow. And when you've got deep snow or if you've got an ice storm, you've got a frozen layer, using your sense of smell is not going to help you. You're going to freeze to death before you can find someone else's caches. and so when things are really cold and really frozen, squirrels tend to stay in their nests. But then when things warm up, they'll come out and they'll beeline to their own caches because

they know where they are. And you'll see in snow, you'll see a squirrel running across the snow and then going straight down, coming up with a nut and going off to a safe place to eat it. Wow. So do they have any memory tricks? I know if I buried something, I'd say, well, it's five feet from the oak tree, four feet from this tree, it must be right here. Did they do that kind of calculation or have any tricks they use?

That is a fascinating question that we don't have the complete answer on. What we have shown in the campus squirrels is that they do seem to organize their caches by nut species. And this is a mnemonic trick. It's called chunking. So if I give you a list of 10 items to remember, and you can categorize those items into a kind of fruit and a kind of dog, for example, then you're going to remember and recall that much more accurately.

And we know this from lab rats. They do this. And so what we found with the squirrels is we gave them a random series of five different kinds of nuts. They would actually cache the same species of nut statistically in a clumped distribution. So you would see a clump of almonds and a clump of peas. and a clump of peanuts and a clump of walnuts. And we interpret that as the mnemonic.

What they're doing is spatial chunking to improve their retrieval. What's interesting is they not only, when they're doing that, imagine you're a squirrel and you're getting this rapid fire presentation of different nuts. And the nuts are different species and sizes. And what the squirrel is not only thinking, oh, okay, this is an almond. where did I cash the other almonds, but they're also measuring the weight of that almond. And we've shown that within almonds, they carry a slightly heavier almond significantly farther. And they're also cashing the almonds at a specific density.

So the more valuable than that, which is basically its fat content, the lower the density because they don't want to, you know, this is a problem. They're constantly stealing from each other. So if you have these great nuts close together, someone's going to come in, say, aha, here's an almond, and they're going to look around quickly and find the others. So the better than nut, the more widely dispersed they are. They're all thieves then. Oh, absolutely. I mean, they're very human-like.

That's what I keep saying. They're, you know, humans are the only primate that stores food. And I think we can learn a lot from squirrels for that reason. I want to talk about what you started our conversation or what actually I started it with, which is something that you run called the squirrel school. What do you teach in that school? Or do they teach you or what exactly is that? So this is an idea I have that squirrels are actually very commonly orphaned in the United States and other countries where a tree nest will be blown down. And the baby squirrels are brought to a wildlife rescue organization.

who raised them for two months and then release them again, back where they were found. And so I was very curious to know what do squirrels, what can they learn during those two months? And so we're working with rescue organizations to study the development of cognition in these orphaned squirrels and with the goal that we'll then be able to follow them after release and see what influences early rearing have on their survival. That's the blue sky goal. Interesting. If you have a bird feeder, which I have a few, you might not be feeling so warmly towards squirrels because they have a knack. They have an incredible, they can break into almost any bird feeder that we come up with.

How do they have that skill? I mean, what, and they'll keep trying over and over again. What is there about their personalities, if I might call it, that allows them to do that? Well, they're generalists. They're facing a year where for the fall, they know exactly what to do. But then come March through August, they have to eat anything they can find. And that's tree buds and leaves and insects and mushrooms and, all kinds of things. So they're really have to be creative to survive. But they also seem equipped

to break into stuff with like their little hands and claws and stuff like that. Well, I mean, right. So think about a squirrel as a burglar with who has built into her head a little chainsaw that can cut through metal. And they've got incredibly, they've got front paws that can manipulate and hold things. They can run on the ground. They can jump. They can climb up a tree. They can go up a tree as fast as they can go down a tree.

Their wrists actually completely can rotate 180 degrees so they can hang easily from their back feet. With their bushy tails, they can leap over great gaps. They really own the physical environment. You putting up a bird feeder is just a challenge to them. Yeah. I noticed that because I know a lot of people who, it's like, you know, spy versus spy trying to outwit the squirrel. I often see these squirrels around my house all the time.

Am I seeing the same ones all the time? Or are there a lot of different ones roving through my neighborhood, scavenging? They're very likely the same. In fact, I think the squirrel in your backyard knows you better than you know them. I'm sure he does. They can live to be 20 years in the lab, but even the field, 12 years. We've got squirrels from Berkeley that we followed for seven years. Yeah.

They're very long-lived. They're, you know, they're, I mean, that's what's so fascinating, actually, about their cognitive development is that it takes them weeks and weeks to learn how to be a squirrel, which compared to a lab mouse who's, you know, born and out by three weeks, very different situation. This is Science Friday from WNYC Studios. in case you're just joining us, we're talking squirrels with squirrel aficionado and expert Lucia Jacobs of UC Berkeley. Do they know when predators are around because there are days where there'll be no squirrels at all and then there'll be a dozen of them? I mean, it seems like they all know to stay away.

And I asked the neighbor once who has a lot of bird feeders or whatever. And she said, you know, there must be a falcon flying around here. Would that be true? No, there's actually a new study showing that they eavesdrop on birds, and they use birds' song to know when predators are around. And they're also, of course, listening to other squirrels, but yeah, they're actually listening to the birds. Yeah. So absolutely. Would you say then, if they're talking to birds, they know what's going on, would you say they're smart or just very skilled or how would you put that?

Well, I'd say that, you know, I would say, are humans smart? they've got all this skill in motor learning, plus they've got all these spatial cognition challenges, which is they're both moving in three dimensions, the tree, and they're foraging in three dimensions, and then they're caching in two dimensions, and they have this months and months of cashing and retrieving and pilfering from each other, and of course they're very sensitive to who's stealing. We've also got some preliminary evidence that squirrels are actually caching in areas near where other squirrels are related to are caching. So what you're seeing in your backyard is squirrels who know each other very well.

There's probably kind of extended kin groups. We know that particularly eastern gray squirrels have these winter nesting organizations that we don't really understand what's going on, but it's clearly something interesting and social. So, yeah, I think they're, they're, you've got a posse out there who's keeping one on you. It certainly seems that way. And, you know, some people who are not squirrel fans, and certainly here in the New York City area, have called them rats with bushy tails. I mean, how accurate is that? Well, like I said, I could, I could insult humans in various ways, too. They're not, they're obviously, they're, they're rodents. But rodents,

also include species like beavers, which are very similar to squirrels in that they have this massive effect on the landscape. Bevers, you know, change the landscape. Squirrels change the landscape. They actually create their own forests. And of course, squirrels are not in the rat family. They're a very ancient lineage. They're about 36 million years old. And the first squirrels from actually quite remarkably well-preserved skeletons look like. squirrels they look like the first squirrel might have been something very similar to a tree squirrel they're also very unusual because they're diurnal so they have better they've better color vision they have their visual cortices are more similar to primate they look more like a monkey than a rat

so there's lots of ways that i think we should think of squirrels as these very smart innovative monkeys, really, that live in our cities. Well, you have given me a different way to think about squirrels, and I think I'm a better person now for that. I have done my job. Thank you very much for taking time to talk with us today, Lucia. Thank you. Thank you. It was a pleasure. You're welcome. Dr. Lucia Jacobs is a professor in the Department of Psychology.

and the Institute of Neuroscience at UC Berkeley. We're going to take a break, and when we come back, we're going to be going from squirrels to the soil that they may be fooling around in, and some of it goes pretty deep. Some of it is going away. We'll talk about the loss, the massive loss of soil around the world. Stay with us. This is Science Friday.

I'm Ira Flato. You may have missed the research when it came out this spring, a paper in the proceedings of the National Academies of Science, reporting on satellite studies of farmland topsoil in the nation's Corn Belt. That states like Iowa and Indiana and Illinois. More than one third of the topsoil in this region, more than one third is gone, eroded mostly from hilltops and ridge lines, thanks to plowing and tilling processes used to perform industrial agriculture.

That topsoil, some of the richest in the world, is carbon-rich and crucial to our, food supply, and yet it's continuing to be washed away, decades after scientists first called out the threat of erosion to our soils. Joining me to talk more about this problem, both at home and around the world, is Dr. Joe Handelsman. She's a soil scientist and director of the University of Wisconsin-Madison's Wisconsin Institute for Discovery. Her forthcoming book is A World without soil, the past, present, and precarious future of the earth beneath our feet. It'll be out in a couple of weeks. Welcome back, Joe. Always good to talk to you.

Thanks, Ira. Great to be here. You know, a world without soil is a grim sounding title. Is it literally that bad than what we're facing? Well, of course, it varies, you know, and every field is different from every other field. Every country is different from every other country. And it depends on the practices on a particular plot of land, what is planted there and how the soil is treated. So the variation is, of course, enormous. But for example, if you had a thousand tons of soil on an acre, which is kind of a common standard used, if we were eroding at 100 tons per acre per year, that would give us 10 years. Now, that's very fast erosion.

The USDA says that across the United States, we're at more like five tons per acre per year. And so that would give us certainly many more decades. But we know that those numbers from the USDA underestimate total erosion because they don't even take into account gullies, which are a really big part of erosion, you know, where you get these big pits in the land and the soil just flows right off. The details are what make this so scary is, you know, like the data you cited from Iowa and the corn belt. There's just enormous erosion in particular areas. And they, some of them, as the article you cited, says, are already devoid of top soil. Yeah, well, let's talk about how we got here.

How did we get to this point? I mean, we've had agriculture for what, 10,000 years? Give us a little bit of the history of the changes that pushed us to this edge. Well, for many centuries, there were many people who farmed in a very sustainable way, and that was partly because the plow had not yet been invented. And so they used sticks and other simple materials to turn over their soil. And it didn't have the destructive effect on soil structure, so the architecture of soil that the plow does. for the most part, societies that have depended upon agriculture for food who didn't treat their soil well, we don't hear from anymore. But the people who have been farming for thousands of years in the same place, like the Maya or the Zuni Indians of the U.S. Southwest or the Maori, those are people who knew how to farm and they know today how to farm, and they have sustained their farms because of the practices they use.

In contrast, when we started very intensive agriculture in, for example, the United States over the last 150 to 200 years, we started intensively plowing, planting single species of plants, which in general were the very extractive kind that took a lot from the soil and didn't put back carbon into the soil. and that reversed thousands of years of soil production in particularly the Midwest of the United States, where we have, as you said, these just amazing, deep, rich fertile soils. You talk about how the invention of the plow invented in one way by Thomas Jefferson. You bring that up in your book as an important part. I find him a fascinating character because, you know, he stood for human independence and the independence of nations, and yet he was a slaveholder's whole life, and how do those two fit together?

He also was a scientist. He looked at data. He loved doing experiments on his own land. He was, of course, a great farmer. And yet, he sort of denied the impact of plowing on the land. And so some of his letters show how he thought that there was really no damage to the land from plowing. But occasionally, you notice in his letters,

that he'll mention something like his son-in-law learned to plow along the side of hillsides instead of up and down. And he thought that was a really brilliant solution because it reduced the erosion of soil. And then, of course, he invented a new kind of plow that turned the soil over that made all sorts of farming that wasn't possible before possible, but that, of course, also degraded a lot of soil across the U.S. And the lost soil isn't just about the food we eat, right, as we've discussed before on this show. And as you're writing your book, soil is also a place where we store carbon, except we're not doing that very well right now. No, we're not. And that's the really sad thing,

because we could be handling a good chunk of our carbon problems with soil. Instead, we're using soil as a source of carbon more often than as a sink. And so the soil already stores three times the amount of carbon that's stored in the entire atmosphere and five times as much as in all the plant life on Earth. So it's the biggest terrestrial bank we have of carbon. But interestingly, there's a lot less carbon in the soil now because of our farming. And we've lost an estimated 133 billion tons of carbon from our soil in the last 150 years. Isn't that appalling? Yeah, it is, but I don't think people really understand, chemically speaking, how carbon works

and its way from the air into the soil as a storage process. Could you get into that a little bit? Well, it's mediated through plants, and of course, that's the process of photosynthesis, which takes carbon dioxide and turns it into plant matter, all sorts of sugars and other molecules in the plants. A lot of that carbon that is fixed through photosynthesis in plants ends up in the roots, and a good portion of the carbon that ends up in roots, ends up around the roots in the soil.

It can be as much as a third of the fixed carbon can end up in the soil. And plants aren't wasteful. You know, they're not fixing carbon just to feed it out to the rest of the world for no reason. Clearly, the microbes that they're feeding in the soil are critical to plant health. And so plants have evolved this mechanism of supporting those microbes through carbon secretion. You know, because on our program, we talk a lot about the microbiome in our bodies, and I'm always pointing out whenever we talk about the soil, that there's a huge microbiome going on in the soil that is disrupted by how we till it, correct? Yes, the soil microbiome is the most complex environment we

know of on Earth. There are thousands of species living together in the soil, and every soil differs in terms of its microbiome from every other soil. So, yeah, there's a magnificent microbiome in soil, and it's changed by planting a plant, by digging up a plant, by tilling the soil. And probably one of the biggest changes we've seen is when we came to this land, I'm talking about European Americans, came to this land and started farming it, we had these deep rooted perennials that filled the Midwest. And that's what created these magnificent soils. Some of these plants will have roots that are as deep as 14 feet into the soil.

Like switchgrass, right? Exactly. Just amazing stuff. Yeah. To look at the root structure. Yeah. And those were feeding the soil, all of those perennials. Then we switch to these crops that extract everything they need from the soil.

And they don't put carbon back in. So, you know, one statistic I learned when I was writing this book that just astounded me was that at the end of a season, a perennial because it needs its energy for the next season, will deposit as much as 70 percent, 7 percent of its carbon in the soil. A corn plant at the end of the season will leave 1 percent of its carbon behind. And so it's not, you know, it's not very hard to figure out how the carbon went down so quickly when we were no longer replenishing it and we were taking so much out with the harvest of our crops. Okay, Joe, now give me some good news. Give me some hopeful news that there's a fix. There's some way we can get around this problem. Today, people are so

depressed about climate change and they feel so helpless to make a difference because it's such an overwhelming problem with so many facets. But soil carbon is one that we can fix quickly and easily. We just need to build the right social structure to do that. So there are three practices that indigenous people have used forever that successfully nurture and protect the soil. And so one is not plowing or not plowing very much. The second is using cover crops so that when there's no crop being grown on that soil, there's still a plant there to replenish it and protect it from erosion. And the third is to intercrop. So use some of these deep-rooted perennials, for example, interspersed with corn plants or whatever the crop might be. With those three methods, and in addition, using

things like terracing to protect the soil from just flowing downhill, societies have protected their soils across the world. And we could be implementing those methods if we had, for example, in this country, the right economic system. But we have these perverse disincentives for farmers to do the right thing. So for example, if a farmer takes 10% of their corn out of production and replaces it with deep-rooted perennials, a study in Iowa showed that this practice would cut erosion by 95% immediately. No kidding. But, yeah, but the farmer gets 10% less crop insurance because they've put 10% less corn in the

field. So is that perverse or what? But we have control over crop insurance. We could fix that. Are there any new innovations or techie solutions that could really make a difference here? Or do we just need to do these really simple things that you're saying? There is so much we don't understand about soil. But at the same time, the methods that practically work are known.

And so, yes, there could be techie solutions. For example, breeding plants to put more carbon into their roots and then into the soil. That would be a very effective solution. And maybe that could be done through genetic engineering or maybe by classical breeding. Or it could be accomplished through the farm management, the practices. Another area is figuring out how aggregates of soil form. We know that bacteria and fungi are very important for sticking soil particles together. And when they're stuck together in clumps or clods of soil, they're much less likely to erode. So if we had more soil architecture like

these aggregates, that would protect soil. And if we knew a little bit more about what helps the soil aggregate, and perhaps we could have a techie solution, you know, adding bacteria or certain fungi or maybe some substrate, carbon substrate that would help them produce the glue that sticks soil together. So yes, I think there are some potential techie solutions, but the ones we have in hand right now are really critical. I think the biggest techie answer that we need is how to control weeds in organic farming. And that may sound like a very, very specific thing. But it's an enormous dilemma because in other kinds of farming,

you can use herbicides to kill the weeds. In organic farming, the only way that they have is plowing. And so they're stuck with this destructive practice because there's no alternative allowed or they become uncertified as organic farmers. So I think we owe the organic farmers some great solutions. on managing their weeds. This is Science Friday from WNYC Studios.

Talking to Joe Handelsman about the threats to soils and how we can restore them. You know, I've heard that some of the high-tech solutions they're thinking about are hydroponically growing plants indoors vertically, right? I'm sure you've seen this. Is this a solution or is it just not big enough to feed the rest of the world? We sort of explored that when I was in the White House. And all of the evidence and the calculations that I could find showed that for vegetable crops and produce, probably that is part of the solution, is to do vertical farming and hydroponics.

But for our staple crops like rice and wheat and potatoes and corn, there's no way that those could be grown hydroponically or in any method that people can even imagine today that would produce enough to feed what we expect. to be the 10 billion people in by 2050. It just, it can't happen. I have to say, you know, I know this has been a problem for decades. We have the dead zone in the Gulf that you talk about, the need for no-till agriculture. I know you've been studying it, what, for years? Why haven't we solved this yet? Well, that's been one of the questions I've had. When I was in college, no-till agriculture had just been invented. And those were really heady times in agronomy. People were so excited about that, and they thought that no till was going to be the answer, that if we stop plowing, we'll stop destroying our soil. And there was an act in 1985, the Food Security Act, that encouraged and

paid farmers to do the right thing and to manage their soil properly and not overtill it. And that started cutting soil erosion right down. It was just, it was dropping steadily. And so I kind of lost track of erosion. I have to admit, once that started happening, I said, okay, we solved that. We're done. But what I didn't know until I started looking into this when I was at the White House was that in 1992 and then subsequent farm bills, the farm bill started eroding the money

that USDA had for holding farmers accountable for these soil management plans. And very sadly, we started seeing erosion start increasing in some areas and leveling off in others. We didn't see that tremendous decrease in erosion rates continue. And so the question is why, and I think it comes down to incentives for farmers. Farming, you know, farmers work on the edge. They are so close to not making a living. that they can't take risks.

And we need to support them to take those risks and the financial risk of saving their soil. Well, I'm glad you've come on our show to talk about all those things because we really do need to hear them. And we need people like you who will tell us, Joe. Thank you so much, Iros. Great to see you again.

Dr. Joe Handelsman, soil scientist, author of the forthcoming book, A World Without Soil, the Past, Present, and Precarious Future of the Earth Beneath Our Feet, really good and timely read. And you can read an excerpt on our website, science friday.com slash soil. If you missed any part of this program or you would like to hear it again. Yeah, subscribe to our podcasts or ask your smart speaker to play Science Friday. And also, you can reach out to us on the Science Friday Vox Pop app. We want to know what's on your mind,

take your COVID-19 questions, and keep you updated about upcoming show topics. That's on the Science Friday, Vox Pop app, wherever you get your apps. Have a great weekend. We'll see you next week. I'm Ira Flato.