The Behavior and Prevention of Wildfires with Adam Coates

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Travis

Throughout January of this year, it's been hard to avoid and even harder to watch the coverage of the devastating wildfires that have been happening in California. But it has led me to become curious about what factors cause these specific fires to spring up, as well as how do different landscapes impact how a fire behaves? How does a fire change when it moves from a forest to a suburban or urban environment? And of course, I'm also curious about what we can do to mitigate the dangers of wildfires in our communities. Virginia Tech's Adam Coates was kind enough to share his expertise on each of these topics and more. Adam is an associate professor of wildlife fire ecology and management, and his research interests include fire ecology in the United States including fire behavior fuels, fire effects, and restoration ecology. Adam shared his insights as to what he believes the factors are that led to the fires in California, as well as how different landscapes, how different environments impact fire, and what we might do to help mitigate some of those dangers in those situations. He also shared quite a bit about how fire, prescribed burning that is, can actually be used to help fight these type of wildfires, as well as where he thinks Smokey Bear may have gotten things just a little bit wrong. So you're surely not going to want to miss that part of the conversation. And be sure to follow, rate, and or subscribe to the podcast. I'm Travis Williams and this is Virginia Tech's Curious Conversation.

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Travis

I'm curious looking at the situation that's happening in and around Los Angeles. What has caused those fires to spring up the way they are? Like what factors are happening there that make these, they're making these happen right now and making them happen to such a bad extent.

Adam

Yeah. So the unique situation in like coastal California is the more Mediterranean type climate, right? So if you, and so this is a different conversation. If we go to Northern California where there are forested areas like more densely overstocked, you could think over mature forest growth. Southern California is much more coastal shrub land, chaperow, manzanita. Like there's different species there that have differing degrees of flammability.

This situation, like this particular one, pretty much weather is the biggest factor in that last year, well in 2023, they had an El Nino year with a lot of rainfall and that rainfall happened to happen in the growing season. And so all of that vegetation just flushes out. They didn't have a lot of wildfire activity that particular year because it was more wet. And so that vegetation lush growth that's green tends to hold on to moisture, tends to be less flammable, right? But then in 2024, I think May the 8th, May the 10th was when the last time they had over a 10th of inch of rainfall in the LA area. And so all of that lush green growth the year before when there was a lot of rainfall leads to a lot of dry fuel material that basically could catch on fire at any point in time. And there's a lot of science we could talk about about vegetation and how different species are more flammable than others and like how some dry out faster and some have.

 

waxy leaves that happen to be volatile and all those things. like in this scenario, there's such a long period of time since it's, they've had a rainfall. doesn't matter what vegetation it would be. It's all prime to catch on fire. so any type of ignition, it could be, you know, there've been wildfire reports where trailers have been, you know, chains that may have on the back ends of trailers that are rubbing on the road can create sparks and they cause ignitions. can be cigarette butts. Like that was the common thing in the 80s was, know, only you could prevent wild, only you could prevent forest fires was Smokey's original slogan. And, know, at the PSAs during the cartoons, we would watch as like, don't throw cigarettes out in the woods and that kind of thing. There's so many other ignition sources than just like, than smoking or cigarettes. It's not putting out campfires correctly. It can be now in California, it's a lot of power line ignitions to where when there's a lot of wind events or around the holidays if you have a lot more electrical surge just by more power needs like when you have that wind and a higher load of electrical demand, if those power lines fail, they arc and they create sparks and that can create fire. So I think there's been in this particular incident, I think the Palisades fire, there was some conversation about it could be electrically caused by power lines. There was also an idea that someone along a trail had actually had a type of ignition occur, not arson or anything like that, but it was something that can't fire or something like that. So really this one is the perfect, and we've had this a couple times in California, of these perfect scenarios of a lot of rainfall one year, vegetation dries out, then you get these really high winds, so it's the Santa Ana winds that are characteristically higher in intensity, so wind speed is really, is pretty high. And also this happens to be a pattern where there's a lot of dry air too. So not only do you have dry conditions overall for fuel, you have dry air being thrust across all this dry vegetation. When you have any type of spark, the flames move so much faster. So that would be true on flat ground, but when you have a lot of slope and a lot of terrain, that creates a lot of strange dynamics for fire too. And even our best science, like you could evolve NASA, you can evolve the Department of Defense the forest service, park service, anybody you can think of that would be managing land plus like the higher end science divisions. Managing fire in that type of scenario is very complicated, even for very smart people, right? Like it does things that are unpredictable and any shift in wind causes fire to behave completely differently. So I think part of what's going on now too is this mix of that we don't understand as well as we probably should at this point, because these are all novel events. Like when this occurs, we don't really have a precedent to go back and look at. You can understand why it's happening, like dry conditions, a lot of wind. And in some cases, having the inability when it's so windy that we can't use some of our more aggressive firefighting tactics of like dropping fire retardant, dropping water, like they couldn't fly in some of these conditions. So when you take that out of their arsenal, you think of it from a military standpoint, when you take that out of your arsenal of how you can actually go against an enemy, and in this case, being wildfire being the enemy, if you can't do some of the major things you would practically do, that limits a lot of the resources you can use, especially on the ground with not wanting to put individual, we're wanting to save individuals from the wildfire, and we're also not wanting to put the individuals that are trying to put the fire out in any kind of danger either.

Travis

What does a fire behave differently depending on the landscape? Or maybe a better question is how does a landscape impact how a fire behaves?

 

Adam

Yeah, that's a great question. like we teach, you know, my students tease me a lot because there are in the in the world of fire ecology, so knowing how fire works, we have stuck with triangles of how we describe things. So it's like there's three factors for this and there's three factors for this. And we boil everything out of these three factors. Of course, they're overly complicated, but you you create a flame with heat, oxygen and fuel. So Earth has readily plentiful fuel sources we have oxygenated environment. really only ever need a heat or an ignition source to ignite those fuels in an oxygenated environment to create a flame. So let's say when we want to talk about fire behavior, the elements that create fire behavior are fuels again, like the type of fuel you have, the composition of those fuels, how it's structured, how they're layered, how fuels are layered, their flammability, like their chemical properties. But then it interacts with weather.

And so if it has been a certain day since rain, right, if there's a lot of wind, what that wind intensity is, what direction the wind is coming from, we measure all these things. And then you throw in topography. And when you throw topography in, if you increase slope by 10%, we expect fire behavior, flame spread to double. So when you begin to start on flat ground, you know, and let's say you have three to eight mile per hour winds, creating a prescribed fire in that condition is pretty, we consider that good conditions. If it's about 25, 30 % relative humidity, three to eight mile per hour winds, like it's pretty flat, you go with the wind and you can burn pretty quickly and create a lot of good, do a lot of good things. Let's say this, shift that though to the Appalachians and you have three to eight mile per hour winds and it's 25 to 30 % relative humidity and you begin to have all these slopes that we go up and down, you probably can't do anything with that. And it's because all that difficulty in the terrain

Wind interacts with the Turing. So if the fire and ignition starts at the bottom of a hill and it begins to move uphill, it's gonna move so much faster. And by the time it crests at the top of the hill, think about the flame links. Like flame links generally take a diagonal fashion. Like you rarely see a flame that's burned straight up, right? So there's always some kind of wind to push it. So as it leans, if it is leaning as it goes up slope, it is rapidly.

Preheating the fuel like the flames even if they're not touching the fuel they're pulling moisture from that material and actually creating Causing the temperature of that material to preheat so when it actually does catch on fire it can rapidly move up a hill so by the time it hits the hill You to the crest it could be crowning out at the tops of the trees Just because it's being pushed up wind and so what's really complicated you mentioned, California again, We teach these dynamics in kind of these, you paint these scenarios. you, you, you think of management from like the more typical, like let's say that we've gone three to 10 days since rain. haven't gone 60 to 90, like we're looking at now, but let's say you've gone three to 10 days since rain and you begin to interact with, um, 20 mile per hour wind gusts, 30 % slopes. And you have that dry condition. Some of what we teach as well, fire should behave this way.

Like it should always move faster up slope and that kind of thing. You have these extreme wind events and wind might be pushing down slope. The fire doesn't know not to like respond to that, right? And so it begins to move downhill and begins to have all these different dynamics. And so some of our normal tactics and how we think about approaching this, we begin to have these novel dynamics, right? And fuel types that we may not always think about with the urban landscape interacting with the wildland landscape.

Travis

I was going to ask you how it impacts of how a fire behaves when you do start to move from like a forest into like a suburban or an urban area.

Adam

Yeah, so fire doesn't behave nicely and no like this is not wildland. This is not wildland vegetation that's burning like this is a car like you shouldn't be burning the car The fire doesn't have the ability to think about that. So You begin thinking about like if it's a material that's holding gasoline like if it's a material that is made out of petroleum products like those things have flammability to them, so it's not just If you were to think of oak leaves and maple leaves and pine needles and those kinds of things, they do have chemical composition that differs. Some of the very small scale science that I do that is very precise is thinking about prescribed fire where we want very specific target objectives. We're burning within three to 10 days since rain and I know that it matters if we burn longleaf pine needles or live lolly pine needles, white oak leaves or southern red oak leaves. It matters the effects on soil. It matters the effects on that water.

Like we get very precise with that. And then you take it out to this really big scale with wildfire and it's like, you know what, I'm less worried about in those situations in many cases with like shrub land, chaparral, when it begins to interact with homes and building materials, the flammability that could be promoted with anything that has petroleum in it is substantial. And you're looking at some of the California stuff now, mean, it's cars melting. It's them finding cinder blocks that are like being overly heated and like not holding their full composition anymore. that the type of not just temperature that you're seeing for these flames, but like the heat being released. We think more about with fire, especially when we measure it about the heat load that is actually coming from those materials. A huge factor in what you would think of with California with wildland, urban interface fuels, trying to be resilient and not that you can completely say we're always taking wildfire away because that's never going to happen. Like lightning can always create an ignition source for this. So you can't ever say that you have 100 % taken away wildfire. But if we can create more resilient landscapes and more resilient communities to say, if a fire does happen, how does the fire not destroy everything that is here? How does it not completely wipe out a community or From a vegetative standpoint, often think about the landscape will respond with vegetation. Like it's just a question of when will it respond and will it respond with vegetation that we want to manage. From an urban landscape perspective, to be resilient.

 

A lot of the advice that comes out of some of the programs called Firewise and Fire Adaptive Communities is to begin to think about using more fire resistant plant materials, more fire resistant building materials. So some of that, you know, things that aren't going to think about plywood or laminated wood, particle board, as that stuff is heated and the glue and the adhesive breaks down, wind can push embers of that material to go and spark fires in other places. So that's a lot of what you're seeing in California now too.

Travis

So it sounds like it's both the intensity but maybe also the speed at which it can spread once it hits that urban landscape.

Adam

So those urban fuels, if you have a lot of wood, woody material, those embers can get lofted and travel miles, right? So that's part of, not only is the fire in California right now moving quickly, just from a flames moving quickly standpoint, all that wind is pushing, they're pushing embers to be, you know, pushed into places that they're not having an active fire spread at the moment, but within minutes, they're going to have an active fire spread because they're basically the fire is getting thrown forward, you know, moving five football fields a minute kind of thing. Like that's, that's unheard of and unprecedented, right? And we, and yet I say unprecedented and yet I don't know how many fires since 2015 I've heard the same, you see these same scenarios. So they are extra, they're in this category. Like what we put as extreme for sure. How do we manage that? Very difficult. You know, I hate to say that it's impossible, but it's just the, the sake of what we know right now of how do that is you have to begin to mitigate fuels ahead of time. And in an urban landscape, how do you do that? You know, I know in San Diego, think there's a fire that's occurring there now, but as of January the third, January the fourth, before all of this stuff in LA, they were looking at some stuff in San Diego, and there was a community where there had been a wildfire, but preemptively, they had created these very large fuel breaks. So it's saying we're going to take away a lot of the more volatile wildland vegetation that could potentially create fuels in like 150 acre blocks. So it's like we're managing, we have created a system to manage for wildfire by saying we're still going to have to keep vegetation there to keep soil in place, to make sure we're not having erosion, to promote water quality, all those things. But we're going to actively manage that vegetation in such a way that if an ignition happens above that area, or below that area and it happens to be pushed into that area, we can actively manage fire within this zone in this fuel break, right? Where we actively begin to manage and think about if a wildfire occurs, once it hits this spot, we have some boundary lines in place to work with this, right? And we already have thought about worst case scenario of we install these in places where We're protecting a community, right? We're protecting a watershed. We're protecting a hospital nursing home. We're protecting areas that have like, in all cases, we cannot let fire come past us. And I think that's a huge part of the strategy now. Out West is thinking how fuel breaks work. You hate to say that as you've seen a severe fire incident like this occur, in the rebuilding of this, do you begin to think about, you know what?

What if some of our constraint on this through zoning and ordinances is we have to create fuel breaks in here. And like, maybe that means some of this high value property for homes and mansions and that kind of thing. Like we're not going to be able to do that. We're going to have to capitalize on putting in fuel breaks here. That, that I think that could have been part of the conversation when Gatlinbury caught on fire in 2016. And yet in a lot of cases, they went and rebuilt exactly like it had been before.

Travis

That's fascinating because I was going to ask you not necessarily on a macro level, but what on a individual level someone might do just prevent it preventative measures of a person like me might might do to limit my or mitigate my risk as much as possible.

Adam

Yep. So it's largely thought about in that FireWise program that I mentioned that it's the National Fire Protection Agency, I think is the NFPA, and it's created that. They think about defensible space. So that's what's really sold to landowners is create defensible space for yourself. So starting like a hundred feet away from your home, 30 feet away from your home, five feet away from your home. Think about the building materials that you're using on your home. Think about the landscaping materials. Think about access to water how you are basically creating for yourself an area that you can manage that you're not thinking as much about federal or state or local entities managing for you. You are taking the extent to say I am using to the best of my ability plant materials that are more fire resistant. I'm using building materials that are more fire resistant. I've thought about access to sprinkler systems. I've thought about access to Hydrants and those kinds of things and ask questions about that preemptively with like local jurisdictions In California, it's become a little bit more about building codes and materials that can be used even for like attic Spaces and how venting can occur because they were finding that some vent systems and attics were actually pulling embers in if embers were created They were literally funneling in through the attics in these these houses So how do you then whatever you've done on the outside doesn't matter if you draw flames into your house, right? So that defensible space is really building housing developments and communities that have, if everybody is working on their defensible space with everybody else that's in that community, right, you create this whole fire adapted community or a firewise community, but not to say gloom and gloom, but like the whole thing that happened in Gatlinburg in 2016, was a, to me it's a hallmark event because it really highlights like, This is so much of what the Appalachian area could look like if it caught on fire because they are flammable species. We do get these periods of time in the fall where you get really dry. And if you continue to have that happen and you continue to have some type of ignition source, man, it's just these communities that are not prepared for thinking about this and homeowners that have chosen to live in the woods and they don't have defensible space, right? narrow roads, only one way in, one way out. All of that dynamic is in place. So I just think more of the conversation about it needs to happen. And there's millions of acres we can be using prescribed fire on, not just to reduce fuels, but to actually think about the forest and the landscape we're managing. And there are some species that are on the decline because we haven't allowed fire to be in the system.It's kind of this thing of like we want to keep wildfire away, but if we promoted more prescribed fire, there's so many benefits we would have, including taking away some of the fuel material.

Travis

Yeah, I was going to ask you how can you use fire to fight fires?

Adam

Yeah, it's the best thing ever. So it kind of in a preemptive measure, a lot of our forest, like if you think of forests specifically, and let's take the Appalachia as an example, like started in the 20s. I think about, think about Smoky Mountain National Park. So as it was founded, you can look in that area from like the, take old trees that have been looked at with fire scars and the tree rings, like so we can date when fires occurred. I'm looking at the charcoal record in soil actually dating when charcoal was last produced.

We can look long-term and see that fire was prevalent in the Appalachian area, in some cases as frequently as eight years, in some cases at 16, like this eight to 16 year window. And all these different studies you can look at in the Appalachians, like you can see fire was repeatedly occurring up until the point about the 20s and the 30s and the 40s when we actively started putting all fires out. Okay. So that means there were species that were present and we still have them. There are species that were present and were dominant when fire was readily put on the landscape. And so for those species to be present and to be prevalent when we begin to see them decrease on the landscape, it's like, fire plays a role in this. But when fire was actively playing a role historically, it had been on the landscape playing a role for a really long period of time. So now when we go back in and say, man, like we need these species to come back, we want them to be prevalent, we're gonna start using fire.

Well, the forest that you're restoring this in is not the same forest that was once fire was readily in there. Like the species, some of the species might not, might be there, but the way that forest is structured is not the same. Like generally it's more dense. We have had invasive species that have come in. We have some novel species that are there. It's that when you just try to come in and use fire to restore those species, it becomes really difficult. And so in a lot of cases it is how do we...prime that forest to be prepared to take fire on. From a wildfire mitigation standpoint, what actually becomes really helpful is you begin to reduce the density of vegetation. And in reducing that density, of course you're taking away some of that amount of fuel, but thinking so much more about how that fuel is structured. So not having canopies of trees that are touching each other not having the forest floor reach all the way basically to the canopies of the trees where the fire can actively spread between these layers in like a ladder. We call that the ladder effect. So we're reducing density. We're reducing like the vertical structure of those fuels. And then when you actually are able to burn the recruitment of those species that we hope that we prefer to stay long term, you're just having to prep them to be ready to facilitate their regeneration and then keep an environment where they're actually will thrive long term. So prescribed fire does this. mean, the very, I guess the common sense thing is it reduces fuels. so that helps with wildfire, but it does so much more than that. When you really think about long-term, what it can do. mean, we, we've done stuff on the coastal plane, not in Appalachians, but in the coastal plane in the longleaf pine ecosystem. mean, it really is. It becomes a completely different ecosystem if you don't include fire regularly and repeatedly. like every two to three years, if you look in Georgia, as part of South Carolina, Georgia, North Carolina, Florida, those systems are resilient to wildfire. It doesn't mean like some of them do catch on fire, but the type of fire that's created, if we were to visually look at it without all of my sciency language on it, like the flames look lower, there's less heat being produced, the forest is open. Within like two to three weeks after you've burned some of those landscapes, the ground can be black. And then within two to three weeks, it'll just green again. Like the plants respond, it produces this kind of fertilization effect. So that's where I fell in love with fire, right? It's like what it can do in the landscape that it promotes, you really don't have it when you take fire out of the landscape.

Travis

It sounds like just hearing you like maybe my very basic summary of that would be prescribed fires can be used to keep things cleaner so that we don't have all this extra stuff that's just going to burn and create a fire that we can't control. But also it helps promote us having the things we actually want to have because they'll be more resilient.

Adam

Absolutely. And it's a shape-shifter, right? It is a defining mechanism in the ecosystem. We often talk about it as a disturbance when we talk about wildfires for sure. You know, not throwing a smokey-bear under the bus, but a little bit thrown under the bus, and that the message of all fire is bad was not really the message to promote, that in some cases where we went and put all the fires out in the forests, some of those fires could have been managed differently right, allowed to take up some space where we're not compromising lives, we're not compromising structures, we're not compromising cultural and historic resources, but allowing those fires to burn within control allowed fire to be in the system. And instead, we just completely said, fire's the number one enemy.

Travis

I did not expect for us to fact check Smokey Bear on this podcast, but here we are.

Adam

I ask my students in my intro forestry class, for any future students that hear this, right, like one of the questions we get in one of the exams is like, is Smokey Bear doing more harm than good?

Travis

You mentioned the fire season earlier and I'm curious, how has what we consider the fire season shifted in the past, maybe decade, two decades? I'm not even sure the right timeframe to ask that question about, but it seems like it's shifted. And so how do you think that it has shifted?

Adam

I can remember as an undergraduate student in 2003 hearing a lot of press about fires in California that were burning into September and October. And then there was a really big one in October of 2005 that was, they were able to detect a lot of the smoke plume with satellites. that was one of first, at least for me, that was one of the first ones I had heard of. Like, man, this is aggressive in the fall, which is not typically when you think of the biggest Western wildfires are gonna be. Now it becomes...We're hearing of fires in October, November, December. This now is in January, right? And so it's it's unprecedented to be able to stretch into the winter months where you think you're either being impacted by, in heavily forested areas in the Pacific Northwest, right? You're thinking about snowfall. If there were fires and big ones in like Yellowstone, snow came and it put it out. Like, but I think in the advent of these changing weather patterns, right? People will politicize this and say, it's either all we've got to do is manage it differently or all I've got to do is think about climate change. It's like, you got to think about both these things. Even if you just say, I'm not a proponent of climate change, but I'm just looking at the weather and seeing what the weather is doing. That in California will tell you, you had a lot of rainfall one year, you had a lot of dry conditions the next, like that means you have fuel there to manage. And so if we're seeing that in a repeated fashion, and that's what we're having to deal with, we have to begin to think about how we deal with that. But with fire season, I think you can't rely on. Okay, it's January, we shouldn't be having fire. You gotta think more critically of like, what has the weather pattern been? And so I think it's much more thinking about that than it is to stick into these rules of thumbs about what a fire season should look like. Because I don't know that we're in that place anymore.

Travis

Was there a time when we really could rely on that?

Adam

I think you would always, I would think, have some, think about a period of time when railroads were being developed, a lot of intensive logging, a lot more interaction with the landscape. I'm sure you could look back in the 1870s and see that there were some really large wildfires when there were a lot of logging operations. But I would say to see it as a precedent where we're dealing with multiple large ignitions in one particular region.

I would say the uptick of that is pretty significant. What's actually really interesting, you're asking a really good question because what's actually pretty interesting too, sometimes you'll see in media stories that the number of ignitions is increasing like on an annual basis. I'll throw a weird nuance into you. There have been years where the number of ignitions recently have decreased, but the number of acres burned has increased. So if you have less ignitions that are accounting for more acreages,

What you're dealing with is more larger ignitions. So the impacts of those larger ignitions, they take more resources, right? But you scale them up to the level of demand, to like a national level, that it's a national effort that's being put forth to take those, to put that fire out. It's escalating in behavior. It's escalating in terms of the personnel that have to be involved and the expertise that has to be involved. And so like we, think it can become, our system of how to put them out is not, We haven't learned less or anything, right? Well, we're at a deficit of knowing how to do this. What's actually increasing is what's changing is the conditions in which the ignitions are occurring.

Travis

The subject of fires, can be kind of, I think you called it earlier, a little bit of doom and gloom. I'm curious when you study this topic and you've talked a little bit about this, but what in this area studying wildfires and forest fires, what gives you hope?

Adam

I think one of my biggest points of hope is from what we've learned in the East of how prescribed fire can be used to do so much good. The more we get that information out, the more we demonstrate that in communities, the more people fall in love with the communities that are created by fire. I think the more we can talk about and demonstrate it, the better off we'll be.

I think what's really happening now too, from what I've seen from the research side that gives me hope, is a lot of the federal, state, local entities are working so hard on this. Like the best minds that I know are coming together to talk about how to do this stuff better and how to think about mitigation. They're also talking about resilience and not just resistance. And so this idea of we're going to have to deal with this disturbance and yet we're going to figure it out. I think some of the most optimistic people I know deal with fire and the most collaborative people I've worked with are in fire because we're all kind of coming together to be like, this is really difficult. This isn't really trying, but I think if we work at this and we work together, we're going to be able, we can't work individually on this, but if we work together on this, we can come up with some solutions. And the fire community is generally a group of people that are very supportive of one another because you can't do it all alone, right? And so it's such a collaborative team effort that I think everybody comes to the table generally to like, what can I do to support you? How can you support me? How can we be doing this effort better? That part gives me hope, I would say, is just the community that's involved with it. The trying thing is just the conversation of automatically wanting to point it out. This has all been mismanagement. People are not managing the fire correctly right now. You know, that doesn't really help anything from a standpoint of this is not a

 

Speaker 2 (32:05.26)

It's not politicized, man. Like it doesn't matter who's in charge of the government. It doesn't matter if it's Democrat, Republican. Like once a fire starts, we've all got to come together and figure out how to manage it. And not only that, but to prevent these future scenarios. so knowing that there's so many levers that get pulled to create a fire and there's so many levers that are going to continue to get pulled to create other fires. How do we comprehensively come together and think of how to manage that system together?

Travis

Yeah, I don't know that fire really cares what political party you might be affiliated with

Adam

You just nailed a perfect way to state that.

Travis

I am curious though, when you bring the best minds together, will you invite Smokey Bear?

Adam

If he brings candy.

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Travis

Thanks to Adam for sharing his insights related to wildfires, land management, and prescribed burning. If you or someone you know would make for a great curious conversation, email me at traviskw at vt.edu. If you liked what you heard, be sure to follow, like, or subscribe to the podcast. I'm Travis Williams and this is Virginia Tech's Curious Conversations.

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