S.7 Ep.7: Beaviculture

Beavers are often seen as a nuisance, but what if they're actually some of nature's most effective forest managers? In this episode of SilviCast, we welcome renowned ecohydrologist Dr. Emily Fairfax to explore the surprising role of beavers as ecosystem engineers. Learn how beaver-created wetlands improve water storage, reduce wildfire risk, enhance biodiversity, store carbon, and influence forest management. Dr. Fairfax highlights practical strategies for addressing challenging beaver activity that impact roads, infrastructure, and timber production. This episode offers a fresh perspective on how one species can reshape landscapes and strengthen forests in a changing climate.

Emily Fairfax, Ph.D.
Assistant Professor of Geography, Environment & Society, University of Minnesota
Emily Fairfax is an Assistant Professor of Geography, Environment & Society at the University of Minnesota and an affiliate faculty member at the St. Anthony Falls Laboratory. An ecohydrologist by training, her research combines remote sensing, fieldwork, and modeling to investigate how beavers shape ecosystems and enhance resilience to drought, wildfire, and climate change. Her work has been featured by National Geographic, BBC, NPR, PBS, Scientific American, the Los Angeles Times, and the New York Times. Fairfax teaches courses in environmental data analysis, data visualization, hydrology, and geomorphology, and is widely recognized for her engaging science communication and passion for beavers as natural ecosystem engineers.

Learn more about Emily Fairfax.

Learn more about Emily Fairfax’s research.

Transcript

SPEAKER_00 0:08

Welcome to Silvicast, the podcast about all things silviculture. I'm Greg Edge, retired silviculturist with the Wisconsin DNR Division of Forestry.

SPEAKER_01 0:17

And I'm Brad Huntnick, a Wisconsin DNR Silviculturist still working until DBH doesn't also stand for Dream, Believe, and Hope. And we're your hosts for today's show. Well, Greg, welcome to Bluegill Shangri-Lab. Uh, Brad, can I take this blindfold off yet? Oh, yeah. Sorry, forgot about that. Take a look. We have arrived at my one of my top secret fishing spots.

SPEAKER_00 0:45

And it wasn't easy paddling with this blindfold, I'll tell you.

SPEAKER_01 0:49

Well, you you did okay with that.

SPEAKER_00 0:51

So, okay, okay, let's take this off. Let's take a look here, see what we see. This is it? This is it. This is your fish nirvana. Brad. This looks like a muddy old beaver pond.

SPEAKER_01 1:04

You know, you're a downer, aren't you? You we haven't even cast a line, and you're already casting aspersions at one of my good spots. There probably won't be any fish. You know, sometimes you need to look beyond, Greg, because this isn't just any old beaver pond. This is a beaver pond in the lower Wisconsin River, which is known for in its backwater, some beautiful big plate-sized bluegills. And my friend, wait, wait for it. This one is gonna be full of them. So we just have to give it a chance. And oh hey, check out, there's a beaver right over there. And you know what? I think you scared it with your negativity.

SPEAKER_00 1:42

Probably scared all the fish, is what you're you'll say as well.

SPEAKER_01 1:45

Well, I'm I'm just I'm gonna shut up now.

SPEAKER_00 1:49

I'll say beavers might be ecosystem engineers, but it works both ways, doesn't it? You know, your pond full of plate-sized bluegills might be someone else's flooded road crossing, their plugged culvert. Why are all my trees dying in this area? You get the drift. Well, it I get yeah, I know what you're saying.

SPEAKER_01 2:11

There is a lot to consider when we add beavers to the equation. Luckily for us, on this episode of Silvacast, our guest is Dr. Emily Fairfax. Dr. Fairfax is an associate professor of geography at the University of Minnesota and an internationally renowned ecohydrologist. Her research uses remote sensing to analyze how beaver-constructed wetlands alter vegetation. For foresters, her work offers a direct connection to forest management and provides actionable insights on how optimizing these natural riparian corridors can serve as strategic firebreaks, protect timber resources, and maintain critical forest ecosystems.

SPEAKER_00 2:50

Okay, but in the meantime, let's just hit the water and see what we got here. Whoever catches the first bluegill doesn't have to buy the beer. Hey, wait, you got one already. Hey, Brad, I've been a busy beaver.

SPEAKER_01 3:14

Thank you to our seasoned sponsors, the Family Forest Carbon Program and the Nelson Paint Company. You make the Silvicast world go round. Dr. Emily Fairfax, welcome to Silvicast. Now, Emily, you don't you don't remember, but I'm part of the the Beaver Management Plan Committee that kind of saw a presentation that you did a little while ago, and I was really impressed. It was really, really good. And I can't I told Greg about it afterwards. I'm like, Greg, we got to get Emily Fairfax on Silvicast because I was really impressed. But I'm guessing that some of our listeners might not have heard of you before. So tell us a little bit about yourself, like where you are, what you do, things like that.

SPEAKER_02 3:59

For sure. So I'm an associate professor at the University of Minnesota. I'm in the Department of Geography, Environment, and Society. And by training, I'm an eco-hydrologist. So I'm really focused on the interactions between water and living things. And it just so happens that has become quite intensely focused on beavers over the last decade or so. So I researched them, I studied them all across North America, many different biomes. And recently I've really started focusing my efforts on understanding the relationship between beavers and climate change.

SPEAKER_01 4:30

Cool. And as far as I know, Greg, you can correct me if I'm wrong here. I will. But you're you're the thank you, Greg. Yeah, that's I you're there for me, Greg, right? Yeah, there you there you go. I got your back, Brad. Yeah, that's what I'm afraid of. You know, keep you in front of me. Okay. But as far as I know, you're our first guest who's been on NPR Science Friday. Our first guest who's been on All Things Considered, which I don't know, makes you a rock star, like on this show. Uh, and you recently served as a scientific consultant on the Pixar film Hoppers. It's true. Which was really cool. Yeah, which is really cool. But how do you get a gig like that? That's definitely a first.

SPEAKER_02 5:09

You just never stop talking about beavers. That's how it all came about. All of these. The Pixar ones started because they had heard me talk about beavers in a webinar and saw a little stop motion video I'd made about beavers fighting fires and asked to talk more about beavers. And then that rapidly escalated into being the science consultant on hoppers.

SPEAKER_00 5:29

Wow. Oh, that's cool. Why has Pixar never contacted us, Brad, to talk about silviculture? I guess uh, you know, it's it's a mystery, Greg, that we'll have to think about that one over a couple of beers. Yeah, yeah. So, Emily, many of us, I think, including me, may not be familiar with maybe some of the historical context of beavers in North America. So I thought it would be a good place to start, kind of go back and uh recognize that. So beaver populations in North America were historically different than they are today. Is that correct?

SPEAKER_02 6:05

Yeah, very different. We used to have somewhere between 100 and 400 million beavers across this continent, which translates to about a billion beaver dams, just absolutely widespread, coast to coast, mountains to prairies to estuaries, to forests, to grasslands, to deserts, everything in between. They were genuinely everywhere. It was like a beaver for every kilometer of stream.

SPEAKER_00 6:27

And so I I take it that that many beaver dams had a significant impact on not only our landscape, but we as foresters, what the forests and uh forested wetlands looked like.

SPEAKER_02 6:40

Absolutely. I work in river restoration a lot, and sometimes people want to get a permit to build a small pond or to build a little dam. And just getting that permit for one little dam takes so long, like a year, two years, as it should, because we know that even just one dam can have a huge impact on the landscape around it and on the delivery of water downstream. So we would never get a permit to build a billion beaver dams, but that's what shaped this continent. And so when we think about restoration, we can't accomplish all of it on our own. We need these little fuzzy engineers that don't pull permits and that don't draw blueprints and that just go about naturally creating wetlands and resilience all across their historic range.

SPEAKER_01 7:21

You know, this kind of maybe this is that philosophical part of it then. So would you say if you were looking, and I'm just thinking, so we're a forester, you're a fisherman, you're anyone, you're out there on the stream, they're kind of looking at a fundamentally degraded condition. Basically, we're we're kind of looking at something assuming it's natural, but then it's because we don't really know what natural looks like.

SPEAKER_02 7:42

Absolutely. One of the most disturbing moments, but also insightful moments that I've had in my career was when I really started looking at the timelines of when my discipline, hydrology, ecohydrology, river science, came to be. A lot of the laws of physics and math that we apply to rivers, a lot of our understanding of what they are and what they should be, came almost immediately after the continental extirpation of beaver. And just this massive change. You lost all this structure from the streams, all of this wood was now going out to sea, the dams were degrading, the wetlands were draining, and then we get Strawler and Horton and Hack and all of these people going out on the river saying, aha, this is how a river flows, this is the shape it should be. So that's what we still think. That's what the PhDs in my field studied was this disturbed state. We didn't get to see that predisturbance state and write the laws of physics for that. We destroyed it pretty quickly. And then we now are trying to maintain this disturbed state by removing beavers and uh trying to continue to force streams back into a shape they actually don't naturally want to be in.

SPEAKER_00 8:47

And then kind of focusing a little closer here in the lake states, you know, we had the cutover period of the 1800s. So they used all those streams for log driving year in and year out. So you not only lost the beavers, right, then you degraded the streams with using it for that transportation.

SPEAKER_02 9:06

And I do like to point out that I think somewhere along the way we were inspired by beavers with our log driving techniques, because beavers do the exact same thing when they go harvest a tree, they put it in their little canals and they float that log where they want it to go. Big difference is that the beavers don't remove every single log jam in their way to do so.

SPEAKER_01 9:24

It's amazing. And I think about Greg, and you, you know, being in lacrosse, you'd be familiar with this too. But like, think about the driftless, where for flood control, basically we had to reintroduce or put small check dams on the streams in order to check the flow of that water coming because it was pretty catastrophic coming out of some of the coolies or valleys that we have here. And I'm just imagining what would that have looked like with beavers in the situations would have been completely different. So so maybe we can go back and maybe just think about some basics because we you know we're we're just like yeah, I I always think of you remember, Greg, there was a saying that Vince Lombardi he would start every football season by saying, This is a football. And so you'd take everybody back to the very beginning and kind of build them up from there.

SPEAKER_00 10:05

Yeah. So maybe here we'll just start with what and wasn't uh somebody taking notes on that? That was part of the joke.

SPEAKER_01 10:11

Well, yeah, the joke is that uh who was it, Paul Horning would say, Slow down, coach, Nitschke's taking notes. So, anyways, that's for the Packer fans in the uh in the audience. But yeah. So we're foresters, we cut down trees, and and you were just saying before, beavers cut down trees. So, what are the fundamental reasons that they're removing trees along streams?

SPEAKER_02 10:32

Beavers use trees for two main purposes. They want that wood to be able to build with. So they'll build dams with that wood, they'll build their lodges with that wood, but they also eat the bark. And bark, especially the cambium, that inner layer of bark, is one of their favorite foods. It's like sugar to them. So they're gonna cut down their favorite trees: willows, aspens, dogwoods, sometimes maples, pretty much anything in the poplar family, cottonwoods, et cetera. They love it. It's their candy. They're gonna cut it down, scrape as much bark as they can off to get that nutrition. And then they will process that whole fallen tree into pieces that are manageable for them to drag around and to build with. And all of this is a behavior that's been really fine-tuned by evolution to get them the maximum benefits for the least amount of work. So for them to be able to eat and build with the same material is ideal. That's what they want, but they don't actually need it. And so we can come back to this whenever. But beavers live in deserts, beavers live in forests made of trees they can't eat, and they still dam and they still thrive.

SPEAKER_00 11:34

So they like those species that you listed, uh, but they'll adapt uh to other species uh when those aren't available.

SPEAKER_02 11:43

They will within uh within reason and constraints. So in Arizona, where the beavers are damming down right on the Mexico border, they are primarily eating cattails and herbaceous aquatic perennials. So they are almost exclusively eating green stuff that's soft. And they will build their dams with mud and stones. And if they can get their paws on some thicker, breedier cactus or cattail or invasive giant breeds, they'll use that as well. They'll use garbage. They don't like to have to split a difference between what they eat and what they build with. It's twice as much effort, but they can do it and they will do it, and they have done it many times before.

SPEAKER_00 12:23

And I live along the Mississippi. Sometimes I notice them chewing on swamp white oak trees, actually. And I thought, well, that seems like a really harsh thing to chew on.

SPEAKER_02 12:34

Yeah, it's definitely not their favorite. I've seen them chew on oak before as well. Sometimes the chewing is not necessarily to take down the tree. Their teeth are ever growing. And if they're in a place where there's not a lot that they can really wear those teeth down on, they'll go to something that they don't actually care about eating. Another behavior that we've just started to observe that I find very fascinating and confirmed with some of my colleagues in Europe that the Eurasian beaver does this too, is in the shoulder seasons, they will scrape the bark off of some of the trees and then lick the sap that's coming out. They don't necessarily want that bark, but they will take the sap.

SPEAKER_00 13:10

They want that energy.

SPEAKER_02 13:11

Yep.

SPEAKER_00 13:12

And these are just maybe some specifics too, but they I think they impact maybe the impact on the forest around them. Do uh beavers always build dams, or in some cases, do they not build dams? And like how far then will they also venture from that stream to impact that forest?

SPEAKER_02 13:30

Beavers do not always build dams. It is something they like to do, and sometimes they'll do it even if they don't truly have to do it. So we'll see beavers living in lakes that have an inlet and an outlet, but the lake provides plenty of water depth to keep them safe. There's plenty of food around, they're not trying to stimulate more growth, and we'll still see a little dam at the entrance or at the exit. And I honestly think they're just bored and they need to build. Because on some of these sites, I've also seen three lodges right next to each other, and only one is active. So it's just too much time on their paws, a little over the top there. But they don't have to. So in big rivers, you they're not damming the main stem Mississippi. That would be ridiculous. But they do live in the Mississippi and they'll bank burrow there. They'll still build their lodges with that dome of wood if they can, but they don't even always do that. So when I raft the Colorado and the Green Rivers out west, we often see them just denning straight into the bank, and there's not enough wood for them to try to build these structures. They're focused a lot more on these reedy things that keep them going. When they do chew, though, they can go quite far. A beaver's territory is typically one to two kilometers of stream length. So anything within that range they consider to be theirs. Even if their dam is up here and then they have to travel a kilometer to get to their favorite food stash, they'll do that. In lake systems, their territories are defined a little bit differently. It's more like a quarter mile of lakeshore. And these are not hard and fast rules, these are preferences that the beavers have. So you can see them going along waterway quite far to get their food. In terms of venturing up onto land, beefers are very awkward. They are anywhere from 40 to 110 pounds as an adult. Wisconsin does have the record of the 110 pounder, so congratulations. But they're not built for overland travel. Their body is like a bowling ball, paddle tail coming out the rear end, webbed feet on back, hands on front.

SPEAKER_00 15:19

Nice.

SPEAKER_02 15:20

Every predator can get a beaver on the land. They're quite vulnerable in that state. So they would prefer to go less than 30 meters inland from their water source.

SPEAKER_01 15:29

So just kind of tip putting that all together, kind of what you were just talking about, it sounds like if we had an area where we're either trying to encourage or discourage this as foresters, we could concentrate on different compositions of forest that would have impacts. And we may either we do it, either we recognize that we're doing it for a purpose, or we could do it inadvertently in some situations.

SPEAKER_02 15:50

Absolutely. And I've worked with places where they've had beavers building their dams and doing their engineering where they're not exactly wanted, but elsewhere on the property was more acceptable. And we've worked with forest managers who are already doing thinning projects to take some of that aspen that they'd cut, put it in a pile to attract the beavers, and then put some cuttings in to try to get them to start growing there. And if you create an ideal beaver habitat, they'll choose that over some slightly subpar beaver habitat, especially given that on today's landscape, there's not that much ideal beaver habitat. There's quite a bit of degradation in our streams, and any step we take towards restoration, we feel great about, but also does improve the chances that beavers will show up, whether you want that or not.

SPEAKER_01 16:32

And would that impact the overall population too? So if you had, and I'm just imagining, say you're in northern Wisconsin, you have an aspen forest versus a like a mixed northern hardwood, they both have that stream going through, there would be a different population or a different number of beavers that would grow in those or you could support in those areas?

SPEAKER_02 16:50

To an extent, the biggest determination of how many beavers are in an area, assuming that it is all acceptable habitat, is just the territory size of beavers. They will fight each other to keep each other out of the other one's space. So if you have a family that set up shop and this mile is their stream, and then some new beaver starts to come in, they will chase it, they will bite it, they will maim it, they will kill it. They do not want to share their resources, which a lot of people don't think about. Beavers are rodent, and you imagine the lot of rodents if you get rodents. You let one in, and instead of one mouse, you have 25 mice, and then it's a thousand mice. It's like a classic biology problem. But with beavers, they are so persnickety about knowing how many trees they have access to and knowing exactly where their good food groves are and the ones that need a break are. They will not accept the randomness and chaos that a beaver they don't know brings. You can have more habitats for more beavers up to an extent, but at some point it's one beaver family per one to two kilometers of stream.

SPEAKER_00 17:48

I think one of the things Brad and I were just when we were going through questions and thinking about was this idea that foresters are often encouraged to manage for long live species in riparian management zones. And for good reason, right? We talked about a lot of those corridors were degraded, they've they're lacking some of the, especially the larger wood within them. But because of these species preferences, you know, is that maybe too simplistic, I guess. Am I asking? Like diversity is really the key in many situations. Is there cases where, oh, we may want to manage for short-lived species like aspen, cottonwood, and willow in some areas close to riparian corridors and other areas managed for long live species within them that may be less preferential beaver food?

SPEAKER_02 18:42

Absolutely. With all management with a goal of resilience, generally the more patchiness, the more of a mosaic, the more diversity you have, the more healthy that system is going to be. We don't want to do restoration with monoculture. It shouldn't be all willow, it shouldn't be all aspen. But having pockets here and there does help ensure that no one section of your stream will go through these really dramatic shifts of over-extracted, under-extracted, over-extracted, under-extracted. The one thing about beavers, though, uh, that I think is fascinating when it comes to exactly how you manage for the different species is that beavers are also managing for their preferred species quite heavily. And there was a paper, I want to say it was from 1929. It's old. There's a quote from it that I absolutely love that says the beavers do not mind the landscape, they farm it. Because it was posing this question of do beavers overextract? Do they cut down a forest and leave? And what they found through these observational studies was the beavers are just constantly going back and forth. And that you don't typically see them completely clear-cut. You'll see them heavily thin an area and then leave it for the time it takes for it to grow back. Many of their preferred species have defense against beavers. Those new shoots taste very bad to them, they're difficult to digest. And so they'll chew it. A lot of these trees are coppiced and new shoots are coming out. The beavers don't like those, so they start foraging upstream a bit. When that downstream area returns to a more well fully grown state, the beavers come back, they start chewing it again. We actually tend to see more living stems in beaver-managed forests than uh in forests without beavers when you're counting their preferred food species. They also are messy, and so they are clipping all these little branches off and they're dragging them around and they get distracted when they're eating, so they'll strip part of the bark off and then they'll drop it. And there's so much water that a lot of these little clippings then put down roots and create new plants. And one of my favorite things to see in sites that had beavers for hundreds and hundreds of years and then were overextracted, and the beavers were killed, is you get these big grasslands or these big meadows, and there's just this sinuous line of willow growing right across the meadow. And you take a shovel and you dig into that, and it's an old beaver dam. Because even when they build with this wood, it will re-sprout and grow. And then those tree roots bind the dam together and hold it in place even when the beavers are gone.

SPEAKER_01 20:59

Oh, that's cool. Somewhere a fisheries biologist is listening to this and uh just coughed up his coffee and said, What? You want aspen next to the stream?

SPEAKER_02 21:08

The panic.

SPEAKER_00 21:10

Yeah. Well, I'm just thinking that, you know, sometimes I think that our concept of riparian management zones is a little oversimplistic. And and in a system that had beavers in it is just what you're saying, Emily. They would be the disturbance factor, right? They would create those pockets that would keep early successional species in areas of the stream.

SPEAKER_01 21:32

You know, Greg, we don't, just you saying that, we don't have any silviculture that models beaver impact as in forest management as a disturbance, not that I'm aware of. Like small gaps, I guess, but we've used all more like wind for stuff like that, or like a medium adjacent to streams. I don't know of anybody who's modeled it.

SPEAKER_00 21:49

Yeah, other than that silviculture trial that Brad had looked up and pointed out, and that they were doing like group selection, so small areas. Is a a forester would consider that like uh a half acre to say an acre in size. And part of their justification was emulation of beaver extraction in those areas. So but yeah, not commonly in something in silviculture we talk about. That's why we're talking about it today.

SPEAKER_01 22:19

Yeah. You know, one thing that I was kind of intrigued with, and you mentioned it in the presentation I saw, and I read about it in some other places, were these ideas of beaver canals. And so not only are they working in the stream, but they're kind of we're building access to the stream, which and so it was kind of interesting. So what are these? And I think you talked about it even as expanding wetlands, which I was like, oh, this is so cool.

SPEAKER_02 22:43

Yeah. So if you imagine what a beaver looks like, from the waist down, it's a very aquatic animal. It's got the webbed back feet, it's got the pedal tail. From the waist up, it is a terrestrial rodent, and they pretty much don't have a neck. Their head goes straight into their shoulders. And that's because they have extraordinarily strong neck, shoulder, and back muscles because they are expert excavators. A lot of their ancestors, way back in deep time, couldn't build dams. They could only dig. And so the top half of them has retained that. And beavers use that to their maximum advantage. So once they've got that pond behind the dam, they're going to excavate these little tiny streams that radiate outwards from their ponds across valley bottoms. They go from in stream to uplands, they go from upstream to downstream. It's not one direction, it's more like a spider web of water. And the beaver does this because it doesn't want to walk on land. These are their highways, these are their city streets. They swim these to escape predators, they float their trees down these to bring them home instead of hulking it overland. But the consequence of this is that the beaver's area of influence goes from being the pond to being kilometer-wide buffers of wetland habitat, of varying levels of wetness. As water level rises and the canals fill, everything gets refilled. The earth is like this huge sponge, sucking up water, putting it in the ground where all the plants can access it during your dry periods. But then during your summer and the water level drops, those canals start to drain off. And so you get these sort of ephemeral bits of wetland in and out, wet, dry. And that's what creates so many different habitat niches, which is one of the main reasons why beavers are a keystone species. A lot of animals depend on the habitats they create because it is spanning so much. There's warm spots, cold spots, deep spots, shallow spots, fast spots, low spots. There's no other wetland type that I'm aware of that intentionally has that much diversity in it.

SPEAKER_00 24:33

So their footprint can get quite large then within those forested wetlands in terms of their influence.

SPEAKER_02 24:39

Absolutely massive. They the impact that beavers have, I consider to be more like a geological force than an ecological force. You don't need that many beavers to truly reshape a watershed and to put strong enough controls on that hydrology that they are equal or stronger than the slope at controlling the hydrology.

SPEAKER_00 24:59

And is is that kind of expansion of the wetland that sort of I think we've read you call it a sponge effect where the water impacts the hydrology in a much bigger footprint, impacting the drought resilience of those lowlands?

SPEAKER_02 25:16

Beavers exert quite a bit of control over the hydrograph, so the delivery of water over the course of the year. When you have your high flow events, whether that's spring snow melt or a big thunderstorm or one of our own dams breaking and releasing a ton of water downstream, that water needs somewhere to go. And what beaver wetlands do is they spread it out over a very large area, they push it through a very rough landscape. There's lots of vegetation there, there's lots of downedwood, there's lots of debris that helps give it time to sink into the soil. Then you enter these dry periods, and because the beaver wetlands were so good at slowing down water during the wet periods, it's now available during your dry period. And that's what keeps your plants healthy during drought. And especially for our tree species that can feel droughts from many years past, where it takes more than one rainy summer to reverse the effect of drought on them. You really want to have just this consistency of water availability. Don't let the whiplash from an El Nino to a La Niña and back and forth drive just incredibly unstable forests. Give them that constant water supply through the soil water, which is what beavers do. And then when you have lightning strikes, when you have campfires, when you have back sparking ignitions, you won't have wildfires burning catastrophically. There will be a lot of natural resilience already baked into that landscape.

SPEAKER_01 26:32

I really like the the name of the paper you had for that Smoky the Beaver, which for all of our, and it feels to me like that's like we should give that paper out to like all of our Western listeners because especially this year, you know, with the low snowpack and just you know, they're gonna be there's gonna be some interesting times ahead this summer, I think, for a lot of them. But having that diversity or those green veins kind of running through the landscape would really be interesting for that. It seems to me like it's just a critical piece missing in the the landscape.

SPEAKER_02 27:03

For sure. And when I first started studying beavers and fire and talking to people about it, there was a lot of what? This is a beaver. Why would it have anything to do with wildfire? But then you think about what the beaver is actually doing. It's widening the wet area, it's connecting a lot of wet pockets together along the stream network. It's basically creating a huge fire break the same we do. It's adding something that makes it fire retardant, it's thinning the fuels around this area that's already a little bit more fire resistant, basically just slowly building up kilometers and kilometers of unburnable landscape. So if lightning strikes there, it's not going to start. But if it struck the uplands and it did start a fire, at least there's something to slow it down, give it pause, take a little bit of energy out. So we don't hit this ramp into these absolutely out-of-the-natural fire regime, catastrophic megafires that are currently plaguing the West and every year creeping eastward.

SPEAKER_01 27:56

Yeah. On the flip side of that, it seems like wow, here are some natural fire breaks that we could implement or encourage as a part of prescribed burning for a number of different purposes. Do you know are anybody thinking of that or doing that on a at any kind of level? Because I'm kind of just curious.

SPEAKER_02 28:12

Yeah, I work a lot with the Forest Service. I work a lot with the Bureau of Land Management. I've worked a lot with nonprofit organizations that help just spread the word about this is a new tool in the toolbox. We're not saying that we should replace any of our existing firefighting or fire mitigation measures. But what if when we're trying to create a defensible space, we incorporate these wet patches into that plan? And we've talked to a number of folks that do wildland firefighting and just ask, what do you think of when you see a beaver pond, when you get dropped into the wilderness and you need to get this fire under control and you see a bunch of beaver ponds, what are your thoughts? And most of them say, Oh, good, don't have to worry about that spot. Yeah, which feels like a pretty simple statement, but it says something. We know these kinds of habitats don't burn. We know that we need more wetlands. There's a lot of ways that we could get more wetlands. Across the United States, we've lost somewhere between 50 and 90 percent of our wetlands. You think about somewhere like Minnesota, where I am, it's a very wet state, but Minnesota's lost half of its historic wetlands. Those are the patches of our fire-resistant natural infrastructure that are gone. We need to rebuild them. People can do it to the tune of about a million dollars a mile when we do it ourselves. Or we can let beavers do some of it and focus our dollars and our time on the things the beavers can't do. Beavers really don't manage a lot of the upland forests. They manage the valley bottom forests. So work together, not on top of each other.

SPEAKER_00 29:33

Yeah, it seems like that should be an element of consideration in planning, both kind of on a landscape scale planning, but also, as Brad said, on a prescribed fire. I mean, we talk a lot about the need for increased use of prescribed fire and a lot of forest systems, but how could you integrate those two together to help you? Seems like some area to be explored.

SPEAKER_02 29:59

Yeah, for sure. Put them next to each other. Do you have a nice band of beaver wetlands? Prescribe burn next to it. Now you've got a huge defensible area instead of just ribbons.

SPEAKER_00 30:12

Season seven of Silvicast was made possible thanks to sponsors like the Family Forest Carbon Program. The Family Forest Carbon Program pays landowners to improve the health of their land and increase the long-term value of their property. The program equips landowners with the resources and support to implement sustainable practices that help them reach their own goals for their woodlands while also improving the health of their forests and our planet. To learn more about how you can access these benefits for your forest, visit Familyforestcarbon.org. Emily, we recently had a silvercast episode which we named Morticulture. It wasn't our name, it was our guest's name. But the idea was to talk about the importance of managing for dead wood as much as managing for live wood. But here we have a species that creates dead wood on the landscape. Like, is there anything known about sort of the impact beavers have on the addition of dead wood, not only to streams, but into that surrounding area as well?

SPEAKER_02 31:26

Yeah, there's been outstanding research on this topic coming out of Colorado and a bit out of Utah. And overall, what we see is that beavers add a ton of dead wood, especially onto the floodplain, when they cut down trees and they leave bits behind, when they have stumps, when those stumps then catch larger pieces of woody material that are being carried by a flood wave and initiate small log jams. All of this is storing a huge amount of deadwood in your floodplain. Some deadwood in the stream channel, like beaver dam is mostly deadwood as well. But it's that deadwood that's one of the main mechanisms that beavers also store extraordinary amounts of carbon in the soil and they get it buried. They get it under the sediment. In addition to having the ability to catch all that deadwood and to create deadwood through the flooding, there's also extremely high aggregation rates. They capture a lot of material and it just gets buried. So there's this very cool study where they took ground penetrating radar across a big mountain meadow and they were looking to see what the subsurface profile looked like. And they saw this weird honeycomb-like structure of woody pockets. And what they realized they were looking at was a matrix of old beaver dams as the meadow continued to agrade and to lift up and build up with new soil and new sediment. The beavers just kept building more dams on top of it and essentially created the meadow, which was the original beaver meadow hypothesis that said that the two main things that make your mountain meadows in the mountains are beavers and glaciers.

SPEAKER_00 32:51

And they also are creating standing dead wood in those ponds, right? So, I mean, I've seen lots of areas that had flooded out, and you have the standing dead snags, seem to be really important pockets for a lot of habitat.

SPEAKER_02 33:08

Yeah, we see those pretty heavily used by a lot of different birds. We also, the number of woodpeckers I saw at a site I was just sat up in the boundary waters on the dead trees around the beaver ponds was extraordinary. But then also eventually those do fall into the water in some orientation. And then that's your habitat for trout, and that's your habitat for juvenile frogs and turtles. So this deadwood continues to live on in many different stages from when it's first standing to when it's partially fallen, to when it's all the way in the water. And unlike some of the other creators of deadwood, bark beetles that are killing the trees, this doesn't create incredibly dense thickets of standing wood that's all dead and dry together. This is very wet deadwood that is spatially spread out.

SPEAKER_01 33:48

What I do like, and Greg, going back to that idea of the morticulture. So one of the things behind that was that you don't have these pulses or just events of dead wood, but you have this regular supply of them that are always available to the things that need them. And I never thought of that until, you know, like preparing for this episode, that beavers kind of do that naturally. They may not distribute them all across the forest, right? You they're going to be close to the to the stream itself in that area of influence that you've talked about, but but I hadn't thought about them as being one of those agents of morticulture that we could actually plan for.

SPEAKER_02 34:22

Yeah, add that to their list of jobs. They're nature's engineers, there's nature's tree morticians, they're just all sorts of things for us.

SPEAKER_00 34:29

They're constantly changing that supply, right? As as you said, Emily, they're moving around, reconstructing, abandoning areas and shifting. That's cool.

SPEAKER_01 34:40

I know there's a forester somewhere out in the truck right now listening to this, going, all right, this is all good, but all well and good, except I can't get across that road now, or that culvert is gone. And then so they're kind of they're probably swearing at us, Greg, right now. But but that being said, you know, I I think that's been part of that conflict, at least in what we see is like, okay, and I think our our good friend Nolan, a hydrologist, said, you know, beavers are kind of like mice, because you see them in the where they are, and they're like, oh, this is so cute, it's fantastic. And then you open your pantry and you see a mouse and go, what the hell? You know, and so when you have one on the road or blocked up the culvert, then it's like, all right, now we got to deal with something completely different. But it sounds like maybe I'm guessing that there is a big discussion too about like, so how do we get those to coexist, right? Like, how do beavers and roads and infrastructure coexist? And so I know you've done a lot of work on that.

SPEAKER_02 35:36

Yeah, there's a few pieces of that question. So there's first just the idea of beavers being something that's difficult and frustrating for a lot of people. And that's true. And that is often true even when the beaver is not actually doing anything to someone. They just see it and they see their dam and they feel nervous because this is a large amount of water stored behind a structure we didn't build. And we, a society, don't generally trust beavers. We don't have designs from them, they don't tell us what they're planning. We didn't watch them build that dam, and we see them as a big goofy rodent without a degree in civil engineering. So we can't trust that they'll hold that water back. But we really should. Beavers have been doing this for seven and a half million years. People have been building dams for maybe 10,000. So we are kindergarteners, they have their doctorates, at least in this. I'm not going to trust a beaver to drive my car or to do my taxes. They aren't experts at everything, but they are experts at dam building. So I think some of this people just need to take a step back and say, okay, this animal actually has specialized in building this wetland. I trust this wetland will stay. Then that moves on to the next question, which is can this wetland stay where it is? Is it right next to a road? Is it flooding someone's house? And when those conflicts happen, a lot of times we just want to kill the beaver, remove the structure, the dam, whatever it is, and move on. But beavers are so stubborn. And once a beaver has decided this is good habitat, it will be good habitat for every other beaver that has ever existed and will ever exist in your watershed. They will continue to come and set up shop there. The only way you can guarantee you're not going to get beavers is to destroy the habitat, which is not what we want. We don't want to pave it. You can make a parking lot, beavers don't damn parking lots, but that's often not our goal. So you will be on this treadmill of forever killing the beaver, removing the dam for the rest of your life, if that's your management strategy. And for some folks, that's what they will choose. But we can also do things like put a fence around the culvert. And if you shape it like a trapezoid, the beaver's brain can't wrap itself around that and they can't damn it. We have found some of their Achilles eels. They don't understand pipes. We can put pipes through the dam, take that water level down just enough so it's not flooding the road. Beaver can't figure out how to plug it up, conflict solved, the beaver either accepts that water level, and it is what it is, everybody's happy, or the beaver doesn't accept it and it leaves, and then it's not good enough habitat. So future beavers will also be irritated by this and leave. We should give ourselves more credit with our engineering that we can outsmart this incredibly clever rodent. There's also the topic of relocation, which comes up a lot, and I think it's this middle ground between lethal removal of the beaver and doing an in-place coexistence strategy. You'll have that same issue. If you pick up that beaver family and move it somewhere else, you will still get another beaver family. But for some folks, they would much rather pick it up and put it somewhere where it is wanted, often on public lands or sometimes on private land where landowner just wants this creature back. But it doesn't change that it's not really fixing the problem. It's just a band-aid.

SPEAKER_01 38:36

Do you know of examples? And I think as foresters, that's we're kind of built for this, right? We're built for thinking long term. Have they had to readjust, like, say, roads or think about where infrastructure goes to accommodate that kind of thing? Or have you seen it successfully done?

SPEAKER_02 38:51

I have. Some of the more successful things I've seen are culvert replacements. So taking out an undersized culvert and either putting in a double wide or switching to a bridge form can make a huge difference for places that are consistently being blocked up by beaver damming. I've seen in park systems, they just move the trail if they can. Maybe your trail was already in a low spot that was flooding every spring, anyways, and now the beavers made it worse. Maybe that's the time to just invest in moving your trail. I love when they put in boardwalks, which is my favorite thing. They're so fun to walk through. And then you're in the wetland and you get this double benefit of being able to expose people to a habitat that is quite difficult for us to actually just be in without that boardwalk. And the beaver's not going to flood the boardwalk as long as you don't build it right at the exact water level. And that is something that we can build our design plans around. I've also seen more extreme examples of that. I've seen people who farm land just decide I'm not going to farm these 60 acres anymore. It's a constant struggle with these beavers. I'm tired of it. I'm not winning. This is a waste of my time. I'm going to make this a wetland and I'm going to pursue this as a mitigation bank. I'm going to be paid that way. Or I'm going to put this into conservation easement because I want something good to come out of this and I'm done. And I think that's also fantastic. I advocate constantly for more financial compensation for landowners that accept beavers back because that animal does provide a benefit to the greater community, not just the individual, but it is the individual that bears the burden of the conflict.

SPEAKER_00 40:18

Is there any ways for a forester who is, you know, maybe trying to design some of that infrastructure for timber sales to, I don't know, to predict where beavers are going to be along that corridor or, you know, or places where they'll have the best likelihood of success of maybe when they do have to do a crossing or place a road that is close to a riparian zone.

SPEAKER_02 40:47

Yeah, there's lots of models that can give you estimates of how good of the habitat it is for beavers. And theoretically, how many dams could it support? The better the habitat, the more dams it could support, the higher likelihood you're going to get beavers there, especially if you know where your nearest beavers are in a watershed. The juvenile beavers stay home with their parents for two to three years, then they get kicked out to go start their own lives and find their own habitat. They would prefer to travel less than 10 kilometers, but they can go up to 100 miles if they have to. They're going to stop at the next best habitat. So if you know you have beavers three kilometers upstream and you have great habitat, you should expect beavers this year. If your nearest beavers are 100 kilometers upstream and there's lots of good habitat between you and them, you probably have more time until your beavers arrive. The other thing that I've started to see some of the timber companies think about out west is when they're modeling the future of their sales and these trees need to grow for X years in order to be profitable, they've had to really start thinking about what is the likelihood my entire forest burns down before I can sell these trees. And what can I do to decrease the likelihood that my entire forest burns down. And more and more I'm finding timber companies and greenery companies having beavers stay in place on their land to be firebreaks and also to be a source of water so that when there is firefighting, there's a video from an old documentary that I've seen of a helicopter coming in, scooping water from a beaver pond. The ridiculous little beaver comes out and slaps its tail to tell the helicopter to leave. Doesn't change that the helicopter now has water to do its backcountry firefighting. Many of these timber operations are in places that are fairly remote and you don't necessarily have water right next door. So get that pond on your land and trust that the beaver will keep it there because that's been their number one goal for millions and millions of years.

SPEAKER_00 42:32

Brad, I was thinking even in our temperate forests, especially with larger properties uh that that managers work, maybe some of that beaver dams and beaver impacts, it's worthwhile to include that in the inventories. So as you were saying, Emily, to kind of know historically along a stream stretch where the habitat is that they're likely to impact might be a way to think about those considerations with infrastructure.

SPEAKER_01 43:03

And Emily, weren't you guys I remember right? It was you guys are working on software to kind of help with some of that too, which the more I hear anytime I see something with AI on it, I'm like, oh, this is just you got to tell me about it, it's gonna be good. But but you guys are actually using it for good here. And it's basically helping. And correct me if I'm wrong, but I think like if we were thinking about for the future, where are we gonna put skid trails or we're gonna put roads or stuff like that, this might be a really big, a big use or a big help.

SPEAKER_02 43:30

Yeah. So we I developed in collaboration with some engineers at Google a model called the Eager Beaver model. And eager is a backronym. We came up with that after the fact to make it work. It is the Earth Earth Engine Automated Geospatial Elements Recognition Model, which is a huge amount of jargon to say you give it a satellite image and it finds your beaver ponds. So it can help you figure out where in your watershed are there beavers that are building ponds and building dams so that you can plan around them and think about I've got beavers here and I've got beavers here. Between, probably going to have beavers here. Is this something I need to manage for? Whether that's preparing for a conflict or encouraging them if that's somewhere you want. We don't have it rolled out entirely to the public yet in a nice software package. The code is publicly available. But we just are wrapping up right now a statewide application of it in California so that they can know where every single beaver pond is in California and think about it in the context of drought and fire and utilize that information just like they would a map of groundwater springs or of previous prescribed burning areas when they're trying to understand what our future of drought, fire, and flood looks like.

SPEAKER_00 44:35

That's kind of really right up that alley. That would be really cool to be able to, you know, precisely map that out across your property.

SPEAKER_02 44:45

Yeah. One thing that we're working on now is we're working with a platform called Zooniverse. This is the same platform that Snapshot Wisconsin is on, where you can go in and try to identify animals that are seen in game camera footage. This fall we'll be rolling out a Zooniverse beaver mapping project. So there's going to be images, and we will train you to see and find beaver dams from aerial images, and you will check yes or no. And that's helping us expand the training data set so that we can roll out this model in the Great Lakes region where it has not been previously validated. So keep an eye out for that. We are always looking for community folks to help us improve our data set.

SPEAKER_01 45:20

Well, we'll keep watching for that when it comes out. That's going to be really cool. We'll be singing praises of it here. Good.

SPEAKER_00 45:27

Finally, Emily, that's a really interesting tool and probably something that our foresters in the field would be interested in. Are there other tools out there that you would recommend for them or even just like for our foresters and land managers managing these forests, what would be your advice to them in terms of working with beavers?

SPEAKER_02 45:56

I guess the overall advice is really genuinely consider working with beavers in whatever capacity you can, because when you protect a beaver, when you allow it to be on the land and to build its wetland, the benefits of that are so far beyond so many other actions that we can take. It feels ridiculous. And like I'm just trying to be beaver spangirl sometimes. But you read the research, on it, and beavers store carbon. Beavers remove heavy metals from the water. They sink out zinc and lead and cadmium and sometimes arsenic. Beavers remove nitrates and phosphates from the water and help prevent alkal blooms. Beavers improve habitat and biodiversity. They create the best duck hunting and the best deer hunting. Beavers just have this suite of benefits that don't even touch the climate change benefits. And if you protect that one beaver, it does them all. It's not like there's a biodiversity beaver that's separate from a fire beaver. So really think if I can leave this here, like that could have so many knock-on effects. And it doesn't have to be all or nothing. If you can protect beavers on a quarter of your property and three-quarters is not acceptable for them, protect that quarter. That still matters. You don't have to be either all in or all out on beavers. And there's lots of tools out there to help you understand where you're going to have beavers, where you do have beavers, where you might want beavers, where you might not want beavers. My lab uses a version of a model that's called the beaver restoration assessment tool to figure out what habitat is the best for beavers out there and where would they be? How many dams per kilometer might they build? It's a big geospatial model that's not always the easiest to run, but there's also a paper version of it, which asks the exact same questions the model does, but you can do it when you're doing a forest survey or a stream survey. How deep is the water in this creek? What plants do you see growing? Do you see their preferred food species? Is it a lot? Is it not a lot? And you count up all these points and it tells you, surprise, you're in great beaver habitat. If you don't already have them, you're probably going to soon. So there's a lot of versions from paper to phone app to a full bulky code that folks can use depending on their skill sets and interests to figure out exactly where the beavers will be and where they are.

SPEAKER_01 48:01

This has been a great conversation, Emily. I really appreciate you coming on today. I I hope everyone else gets as much out of this as I got, because this was fantastic.

SPEAKER_00 48:09

I think from us as foresters, silviculturists, it gives us something to think about about a species that is having maybe you know, you mentioned it right in the beginning, Emily, that they're basically forest managers also and trying to work with that within the system so that kind of our mutual goals are achieved. It's just uh gave me a lot to think about in terms of that management and that planning aspect uh along with this species.

SPEAKER_02 48:43

Yeah. They can for sure be a difficult colleague sometime. They are not always the easiest to work with, but usually they're that kind of colleague where once the project's done, you're like, all right, I'm I am glad we work together.

SPEAKER_00 48:56

Yeah. Well, they're no they're no more difficult than the colleagues I work with on a regular basis.

SPEAKER_01 49:01

I've already got a nickname for a colleague of mine, so this is gonna be great after this episode.

SPEAKER_00 49:06

Life is good. Thanks, Emily, for joining us today and for this conversation. It was really good.

SPEAKER_02 49:12

Yeah, of course. I'm always happy to talk about beavers.

SPEAKER_00 49:15

Take care.

SPEAKER_01 49:21

Greg, that conversation was fantastic. I hope everyone else got as much out of it as I did. And it made me think of a term. Hmm. Uh, what term is that, Brad? Well, uh, this is oh, can I say it now? We're riding the Silvasaurus.

SPEAKER_00 49:37

Okay, we're on the Silvosaurus Silvictionary here.

SPEAKER_01 49:42

We are in the Silvasaurus. So today it made me think of ramicorns. Pardon? Because you know, ramicorns are fuzzy little beasts, they run around to have you do you remember? Like, we've seen a lot of ramicorns and we've been out late at night. Yeah, they're so fuzzy, they're so fuzzy. Just just like a beaver. Yes, yeah, kind of like that.

SPEAKER_00 50:06

No, I don't I don't get it, Brad. You're gonna have to explain further.

SPEAKER_01 50:10

Whatever. It's you know, it's you don't question how the mind works, Greg. Just go with the flow, right? Just let it flow over you. I do it every day. But I read the term recently and I was like, well, that's a term that I was not familiar with, and so I had to look it up. Yeah, ramicorn is a term that's found in the dictionary of forestry, and let me read it for you. A ramicorn is a large high-angled branch that often results when one member of a fork is partly suppressed by a more dominant member. So if you have two branches, one takes the lead and the other is off to the side. But it's an angled lead. So it's it's an angled lead. And oftentimes when you get a board sawn where that stem comes off, that knot is called a sucker knot. What's usually interesting about it is they can be abnormally large branches, and so it's not just any branch, and they're usually at sharp angles and acute angles from the bull, and they're there for a long time. You know, and I think I've seen these like in white pine where you see like from a beaver or a weevil attack, and you've kind of seen that coming through.

SPEAKER_00 51:16

Kills the terminal branch, and then a real uh aggressive or vigorous side branch sort of takes over.

SPEAKER_01 51:24

Yeah, and I've never used that term to refer to them, but I kind of like the idea that we have a term that refers to them. So I'm gonna start using this.

SPEAKER_00 51:33

Does it have anything to do with like a ram's horn? Like it's a big thing sticking out to the side?

SPEAKER_01 51:41

That's a great question, Greg.

SPEAKER_00 51:43

Well, come on. If you're coming up with terms, you gotta have the background on this.

SPEAKER_01 51:48

Well, that will be a mystery that we will have to solve. We'll talk about it in the next beaver dam that we're fishing in. Okay. Hey, did you and actually did you see the size of the bluegills that I caught?

SPEAKER_00 51:58

Uh I did. Yeah, those were nice. Those were nice. It was pretty cool. I didn't understand why you gutted them rather than filleted them, but yeah, well, we'll it yeah, we'll talk about want and waste another day.

SPEAKER_01 52:10

Yeah, well, want and waste comes at a later episode.

SPEAKER_00 52:12

I can't wait to be out in the woods and go, look at that ram a corn. Yeah, that's I bet there's a big sucker knot behind that.

SPEAKER_01 52:19

Yeah, you can thank me when it happens. Thanks for listening to today's episode of SilvaCast. If you have ideas for future episodes or a question for the drop box, please let us know. Hey, and a shout out to Ellie and Nepal. We got your message. Thank you for listening. You may be our only listener in Nepal, but we truly appreciate you listening. So wherever you are in the Himalayas, looking at a glacial mountain stream, we really appreciate you listening. Anyone else, you can all send in your stories to, but we really appreciate hearing from Ellie. You can reach us at UW Stevens Points Wisconsin Forestry Center by emailing wfc at uwspoted. Feel free to include a sound file of your question or the any kind of comment if you like. Remember, we learn best when we wrestle with questions, so please keep them coming.

SPEAKER_00 53:16

And take care, everyone. And as always, thanks to our team, Susan Barrett, our executive producer, Joe Rogers, editor, and IT Jedi Master, theme music by Paul Freder, and of course, UW Stevens Points, Wisconsin Forestry Center.