Climate and the Future of Forests with Dr. Tyler Hoecker

A conversation with Dr. Tyler Hoecker, who studies forest ecology and the changing dynamics of fire as the climate warms. This episode was recorded in August of 2023.

Glacier Conservancy: https://glacier.org/headwaters Frank Waln music: https://www.instagram.com/frankwaln/ Stella Nall art: https://www.instagram.com/stella.nall/

Climate change in Glacier: https://www.nps.gov/glac/learn/nature/climate-change.htm Dr. Hoecker’s research: https://www.sciencedirect.com/science/article/abs/pii/S0378112721009051

A conversation with Dr. Tyler Hoecker, who studies forest ecology and the changing dynamics of fire as the climate warms. This episode was recorded in August of 2023.

Glacier Conservancy: https://glacier.org/headwaters Frank Waln music: https://www.instagram.com/frankwaln/ Stella Nall art: https://www.instagram.com/stella.nall/

Climate change in Glacier: https://www.nps.gov/glac/learn/nature/climate-change.htm Dr. Hoecker’s research: https://www.sciencedirect.com/science/article/abs/pii/S0378112721009051

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TRANSCRIPT:

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Lacy Kowalski: Headwaters is supported by the Glacier National Park Conservancy.

Peri Sasnett: This is Headwaters, a show about how Glacier National Park is connected to everything else. My name is Peri, and I'm talking to you from the dense forests of northwest Montana. This episode is an interview that my co-host Daniel did with forest ecologist Dr. Tyler Hoecker about how wildfires exacerbated by climate change are upending our forests. This episode is part of a series of conversations we've been having with a wide variety of climate change experts. These episodes don't have to be listened to in any order, each one stands on its own. And they all focus on a particular aspect of the way the world is being altered by the burning of fossil fuels. Over the past century and a half, human activity has released enough greenhouse gases to warm the Earth's climate over one degree Celsius, with only more warming on the way. Throughout 2023, Daniel sat down with experts to talk about how that warming is altering Glacier National Park, our lives and our futures. [drum and synth beat starts to play] I find fire fascinating, so I think this conversation was one of my favorites. I feel like I've heard most of the usual stories about wildfire so many times, so I was really excited to hear about Dr. Hoecker's research on how forests are responding to climate change. It felt like a new angle. I learned a lot, and I hope you do too.

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Daniel Lombardi: So, Dr. Tyler Hoecker, welcome to Headwaters.

Tyler Hoecker: Thanks so much for having me.

Daniel: It feels pretty good that we're talking today, or auspicious or bad, on like just this week the smoke really rolled into the park. We have several new fires burning right around us. It's very much fire season, so it's a good time to have this conversation. Will you introduce yourself and talk about kind of your job and the work you're doing right now?

Tyler: Sure. So I'm Tyler Hoecker. I'm a research scientist at the University of Montana in Missoula. And right now I'm doing research trying to understand how climate change is changing fire activity across the western U.S. and trying to project how fires and forests might change into the future.

Daniel: How did you get into fire stuff, like how did that become the path for you?

Tyler: I think everybody is sort of drawn to fire, in a, in a weird way, you know, fires are pretty important, has been an important like catalyst, you know, for civilization. And so I think it's sort of just a compelling thing.

Daniel: It's kind of a universal concept, that fire and flames draw your eye and like draw you in.

Tyler: Absolutely. Absolutely. It's hard to think about forests in the West without thinking about fire. I remember as an undergrad, I took a a forest ecology and policy class, and we went to a community fire meeting. And I just remember being really fascinated by the process. And it was clear to me pretty quickly that it was really important at shaping forests in the West. And so I was really interested in understanding it. And, you know, it's sort of interesting to think back on that. You know, that was 2010. And, you know, I think fire scientists probably understood what was what was unfolding in terms of fire in the West. But I don't think anybody would have been able to really predict, you know, what's happened in the last 13 years since in terms of the amount of area burned every year. And, yeah, the types of fire events that we're seeing every summer now.

Daniel: Yeah. So let's jump into some fire ecology. At one point I was hiking up Mt. Brown and it was kind of in the fall, early fall, the fireweed was blooming and like the sun was rising and kind of glowing through it. And there was the cloud layer was like fog all in the forest. And so I was walking through that and it had burned, you know, like a year before. So everything is charred and crisp and like pretty black. There's no living trees. But in that morning light, it was so beautiful. And for me it was kind of like a pivot point. This, like black backed woodpecker, flew down and landed on the tree in front of me and was feasting on beetles that like the fire-killed trees. And I was like, Oh my gosh, like fire is not ugly. The aftermath of fire can be really beautiful. And I knew intellectually that it's also ecologically important. So maybe we can start with something like that. Like why, why is fire important in a place like Glacier National Park?

Tyler: So one of the things that I like to, to maybe start by kind of acknowledging or stating is that fire, in seasonally dry places, is inevitable. I mean, it's important to think about the benefits and the risks and things like that. And it's also important to acknowledge that it's inevitable. And it's just it is. And it will always, it will always happen in seasonally dry places.

Daniel: Yeah. So like, this place gets dry. There's lots of things growing here -- trees -- it's going to burn.

Tyler: Exactly. And so that means that everything that we see when we look at forests in fire-prone places are shaped by fire. Right? And so the species that we see, that's the forest structure or kind of the age of the trees and the way that they're arranged on the landscape in a place like Glacier, that that is driven primarily by fire and the history of fire.

Daniel: The animals and the trees that have lived here for millions of years have lived here with fire for billions of years. They always have coexisted.

Tyler: Exactly. But the biggest thing is that fires create what we call, like heterogeneity. You know, the opposite of homogeneity. Heterogeneity is variation in species composition, in structure and physical structure of a vegetation. And that heterogeneity confers resilience, right? And so a forest and an ecosystem that's heterogeneous, that's diverse and variable is going to be more resilient to future disturbances, to different pressures and stresses to insects and pathogens to drought.

Daniel: So would you say, when you say that fire creates heterogeneity in an ecosystem, in Glacier National Park, it kind of sounds like you're saying fire creates complexity.

Tyler: Absolutely.

Daniel: Okay. And that creates complexity means different habitats, which means that allows for biodiversity for more kinds of life to live in one place.

Tyler: Absolutely. So biodiversity basically emerges from complexity. Right? A complex system has more niches, has more opportunities for different types of organisms, and that creates a richer system.

Daniel: Compared to, say, a cornfield or like a forest that's all just one kind of -- lodgepole pine say. You know, it's just all one tree. So only certain kinds of birds, only certain kinds of animals are going to live there. You start mixing that up, you burn it and different trees start growing, then you're getting more complexity. You're getting more biodiversity.

Tyler: Yep.

Daniel: That's cool.

Tyler: Yeah.

Daniel: Not every tree in the forest has the same adaptations to fire. Some trees are adapted where they like a little bit of fire. Others, they only grow in places that probably aren't going to burn. So maybe you could break that down a little bit. Like, what are the strategies for trees? What are your options?

Tyler: Right. So trees or plants, you know, have these, as you described them, quirks, right. These characteristics. And in, and in sort of the ecology world we call those traits, but I think makes more sense to call like a strategy. So basically your options are to avoid fire, to be a species that can either hang out for a long period in the understory and during a long fire free period, or can tolerate cool, wet sites where fire is less common and happens never or very infrequently. So those are species like subalpine fir, Engelmann spruce, western red cedar, western hemlock. Those are trees that grow in regions or in microclimates that tend not to burn very often or tend to burn very infrequently. And so there's a long fire-free interval in which they can establish and become dominant.

Daniel: So if you're familiar with the park, then like somewhere like the Fish Creek campground or the Avalanche area. These are like little pockets in the landscape where a creek goes through the middle, they get a lot of rain right there, they get a lot of snow. And so you have a lot of cedar and hemlock, these forests that are really dense and dark and mossy, you can just feel that it doesn't feel like fire comes through there very often.

Tyler: Exactly. Yeah. And so the other strategy or another strategy is to resist fire, and to survive fire as an individual. So those are species like ponderosa pine, western larch, and they have things like thick bark. They drop their lower branches, so that there aren't ladder fuels that would carry flame to the crown. They have rot-resistant wood, so that when their trunk is scarred by fire, that exposed wood doesn't rot. Hmm.

Daniel: And then there's all kinds of species that are-- there's all kinds of other strategies, too.

Tyler: Yeah. And so there's there's maybe sort of a third strategy around what we might say, fire embracing, or fire resilient.

Daniel: Fire loving.

Tyler: Yeah, fire loving. And so these are species that, like in the case of lodgepole pine, they've adapted a strategy where individuals are killed, but they have mechanisms for their genes to carry on. So older lodgepole pine tend to produce some serotinous cones, and they're, they're cones that are closed, and they're bound up by resin. And serotinous cones stay closed until they're heated by fire.

Daniel: They're waiting for fire.

Tyler: They're waiting for fire. And so this is a strategy. This is like putting all your money under the mattress and waiting for that opportunity to strike it big. Right? So the individual bearing those cones is probably dead, as are all of the individuals around it. But what you have is this environment that's perfect for lodgepole pine seedlings. It's bare mineral soil, it's high light, it's low in competition. And so they seed, you know, millions of seeds onto a, into an environment that's perfect for for their regeneration. And so then you have a new single-age cohort that recovers after the fire.

Daniel: Interesting.

Tyler: The other sort of version of being a fire-embracing, or fire-resilient, is to be able to resprout. So that things like aspen or cottonwoods or shrubs.

Daniel: That is they're not good at surviving the fire, but they'll grow back faster than every -- all the other trees. Right.

Tyler: So they survive in a way, their underground structures survive. The top is killed and they can re sprout from that underground. Those underground root structures.

Daniel: It doesn't have to regrow its roots, it's already got them.

Tyler: Yep. It's starting with a bit of a trust fund there and so can do really well.

Daniel: So there's we have all these trees in the park. We've got ponderosa pine in the North Fork, we've got cedar, we've got big dense forests of lodgepole and larch. We've got it all in Glacier. It's a pretty diverse place. So what is the fire regime or what is the history and pattern of wildfire, naturally, in Glacier National Park?

Tyler: Yeah. So, you know, one of the things that's really fun and cool about studying fire in Glacier is that high tree diversity. So you have all of these different individual species that sort of respond and coexist with fire in different ways like we talked about. And what that also means is that the fire regime across Glacier is different depending on where you are. So most of Glacier is what we would call Subalpine forest. So that's forests that are dominated by species like Engelmann Spruce subalpine fir douglas fir, larch, western white pine a little bit.

Daniel: Okay.

Tyler: So these are sort of the mid to high elevation, you know, before you get into that alpine whitebark pine zone. Those are forests that burn infrequently and at high severity. So infrequent in that context means every 150 to 300 years or so.

Daniel: Wow.

Tyler: So that's what we would call infrequent. Mm hmm. And because there's this long time period between fires, there's a long opportunity or a lot of opportunity for biomass to accumulate. And so that means that when fires do come through, they burn at high severity, they burn really hot, they kill most of the trees, they burn off the organic matter on the, on the surface of the soil. There are some places in Glacier that have a more frequent and less severe fire regime. So places like the North Fork, because they're in sort of a warm, dry microclimate and because they have species that can survive fire, that sort of creates the conditions for a more frequent fire regime, which would be burning every 5 to 50 years or maybe 5 to 100 years.

Daniel: So it could be pretty common. Yeah, every five years.

Tyler: Yeah so that's-- and then at low severity, meaning that relatively few individuals are killed in a fire. Right. So maybe some trees are killed, but most of the large mature individuals survive and maybe the small trees in the understory are killed. Hmm. It's also important to note that in a lot of places, those frequent fire regimes were supported by human burning, you know, by by cultural burning, by Indigenous people.

Daniel: Okay. So the park has some areas that historically would have burned pretty regularly, maybe sometimes even as much as every five or ten years, and burning at a fairly low severity. It's clearing out the shrubs and burning the grasses around the trees, burning some of the little trees. But most of the park is stand-replacing fires. Most of the park is not burning that often. In recent years we've had the Howe Ridge fire. We've had the the Sprague fire. What kind of fires are those? Are those the frequent fires or the infrequent ones that happen only every few hundred years?

Tyler: So those two fires together were a really cool opportunity as a scientist, because what we had there was fires that burned in forests that were historically pretty similar on either side of Lake McDonald. And those both of those fires burned almost into that Cedar-Hemlock zone, but mostly in that kind of mid-elevation subalpine forest zone. And the Sprague Fire was really kind of what we think of as typical of the historical fire regime in Glacier. So fire where those trees were in that range of 150 to 300 years old. So you had old forests, pretty big trees, relatively dense and had not experienced fire for a long time.

Daniel: So this the Sprague fire then, I remember when that started, and that's the fire that ultimately burned down Sperry Chalet. This-- this is a fire that you're saying is what we would expect in Glacier National Park, that those trees, 200, 300 years old, they're kind of right on schedule to to burn.

Tyler: Right.

Daniel: But then now things are changing. What is the relationship, if we step back for a second, between fire and climate? We know things are getting hotter. I'm sure that's changing fire here.

Tyler: Yeah. So all fire regimes are driven by three things, basically. By vegetation, climate and ignitions. So we kind of we talk about like a fire triangle defined by those three things. But which is more important or more influential varies from place to place. And so in a place like Glacier, ignitions are not particularly limiting, and vegetation is not particularly limiting. You know, if you think about the forests of Glacier, they have a lot of biomass, right? We have a lot of trees. There's plenty of fuel on the landscape. Okay. And so what tends to limit fire activity in Glacier is climate.

Daniel: Because we also have a lot of lightning strikes.

Tyler: Right. So we almost always have the vegetation ingredient. We almost always have the ignition ingredient, at least during the summer. And what determines whether we have fires and in particular what drives whether we have big fires -- big fires that burn for a long time -- that's really driven by climate.

Daniel: So to put it simply, there are always enough trees here for a good fire. It's really just, is the climate dry enough for it to happen?

Tyler: Exactly. Yeah. There's always enough vegetation on the landscape to burn. And it's whether or not the, the environment and the weather is suitable for burning.

Daniel: So now maybe tell you could tell me some more about then, what are the trends? What's been happening in recent decades? What are we kind of forecasting to see? I mean the headline we know is it's, it's getting hotter. Climate change is warming this place up. How is that affecting fire?

Tyler: Sure. So because climate is a, is a big driver of all fire regimes, and especially in places like Glacier, where climate is the main driver of the fire regime, fire activity is really sensitive to changes in climate.

Daniel: Like big picture, what are we seeing across the American west? I mean, I think we're seeing more fire, right?

Tyler: Yeah. So we're seeing we're seeing longer and hotter fire seasons. So we're seeing that fires can happen for more of the year. They can last longer and they're burning hotter and burning at higher severity, affecting more of the landscape.

Daniel: One study I've seen estimated across the broader American west, something like doubling. We've already seen a doubling of the amount of wildfire burned since the eighties.

Tyler: Yeah. And so we also know that we can see this trajectory of increasing area burned. And the other thing that's different now is that these forests are burning and then trying to recover in a climate that's very different than it was 100 years ago.

Daniel: This is really where your research comes in then.

Tyler: Right, and then seedlings are trying to reestablish in an environment that's several degrees warmer and much drier than it was when the last fire happened. So it's kind of this combination of increasing area burned and increasingly warm, dry conditions that make it more difficult for trees to reestablish after a fire. So that's part of what makes modern fire activity so different.

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Daniel: So maybe we could talk then now about the Howe Ridge fire, and as an example of kind of how the regeneration is changing.

Tyler: Right. Yeah. So some useful context for the Howe Ridge fire is that it burned entirely within the footprint of the 2003 Robert Fire. You know, that was the conventional wisdom in the Northern Rockies is that places that have recently burned are unlikely to burn again for at least a few decades.

Daniel: But so then in 2018, 15 years later, it burned again, like really just the exact same spot. And that was unexpected for fire managers and scientists. Right?

Tyler: Right.

Daniel: Okay. I was watching the fire the night it really took off, burning downhill in a way you wouldn't expect. And a, a woman was watching and crying about the fire. And I was talking with her and I, I didn't really know what to say. And I was like, "well, yeah, I, I didn't think a fire could burn in a spot where it had already burned just 15 years ago." And she was like, "Well, that's climate change. I know it is." And that kind of stunned me. But I was like, I guess she's right.

Tyler: Yeah. And so I talked about how the area that was burned in the Sprague fire was really old and this forest was sort of at a stage where it was, you know, sort of ready to burn. Right. And when that fire burned through, there was all these sort of material legacies left that allowed the forest to recover rapidly. Right. So there are stands that had a lot of serotinous cones. There were big live trees all around the edge of the burned area to, to seed into that area. And when we went back into the the area that the Sprague Fire burned, it was basically like walking through wildflower meadows. It was like a sea of hollyhock, like I've never seen.

Daniel: Wow.

Tyler: And then there'll be other areas that were like a sea of fireweed. Hmm. And that's sort of like what we expect post-fire landscapes to look to look like in the Northern Rockies.

Daniel: So this is really fire being an agent of change and diversity and beauty, the kind of the way we'd expect fire to be here historically or traditionally.

Tyler: Right.

Daniel: And that's the Sprague fire. That's really interesting.

Tyler: Yeah. And so I wasn't here for it, but that's what I imagine things looked like after the 2003 Robert Fire. So the Robert Fire, or like the landscape following the Robert fire, regenerated similar to to what is happening right now after the Sprague fire. Mm hmm. And so we had these, you know, really dense stands of mostly lodgepole pine and larch. But some of the other species that we would expect, like Doug fir and spruce and fir were regenerating in that site. Mm hmm. And then 15 years later, a lot of that standing wood that was killed in 2003, a lot of those snags fell. And so you have a ton of coarse woody debris, sort of matchsticks all across Howe Ridge. So it actually creates these conditions that are really conducive to very high severity fire.

Daniel: Yeah. So basically that's lots of big trees that died in 2003, they're laying on the ground, laying on top of each other. And then all in between those, coming up, are young baby trees that are, you know, less than ten feet tall sometimes. And they're really close together. So now you've got big logs and lots of little bushy trees all mixed together really tightly.

Tyler: Yep. But if you have all these matchsticks and you're going weeks into the summer without rain, you have an opportunity to really dry out these big fuels. And you have all these fine fuels, like you said, sort of right there, intermixed with all of the dead wood. And then you get these warm, dry conditions, you get an ignition, and you get some strong winds, and that can that can burn these very young forests in a way that we haven't observed much before the last few years.

Daniel: Hmm. So then that's where things are a little bit unexpected.

Tyler: Absolutely. So we measured both of these fires two years post-fire. Okay. So the Sprague Fire we've sampled in 2019, and Howe Ridge we sampled in 2020.

Daniel: Two years after they burned.

Tyler: Yep. So kind of the key pieces of information that we were after was, the density of trees -- how many trees are there, you know, per area? And what's the composition? What species are they? Mm hmm. Because we wanted to know how the forest that was regenerating was similar or different to the forest that was there before. And so in general, what we found in the Sprague Fire was that the composition that we sampled in those first few years post-fire was pretty similar to the composition beforehand. So there was a little bit less of the spruce and fir, which you might expect because they're very fire sensitive and they're a little bit more shade tolerant. But we had basically the full suite of species that we saw before the fire, we were able to identify post-fire.

Daniel: So the Sprague Fire like, is an example of the forest regenerating kind of as you'd expect. You see most of the trees that were there, that were burned, you see most of them growing back up.

Tyler: Yeah.

Daniel: And then you're comparing that to the Sprague fire, to the Howe Ridge fire.

Tyler: Right. And so we did the same thing in the Howe Ridge fire, as I mentioned, you know, fires are are really complex and heterogeneous in terms of their severity. We went to places that burned at high severity because we were really thinking about the future, and thinking about as the climate becomes warmer, it's really these places that have burned at high severity that are going to give us the best sort of window into the future climate -- where forests are headed.

Daniel: You didn't survey randomly. You picked intentionally areas that burned really severely.

Tyler: Right. So it's not that those places characterize the whole fire or and certainly not that they characterize the whole park, but they characterize what happens in a forest when it burns twice and when it burns at high severity twice.

Daniel: So what happens?

Tyler: So now we've burned it twice. There's almost no material left on the landscape to provide these shaded microsites for seedlings. We're really far now from seed sources and any of the seed sources that might have been within that burned patch. Like serotinous lodgepole pine haven't had the opportunity to develop. Serotinous cones don't develop on lodgepole pine until about 30 years in. And so you have no serotinous cones.

Daniel: Because they weren't ready.

Tyler: They didn't have long enough to develop and mature and then even non-serotinous cones, these trees are just 15 years old, right? So they're just approaching sort of sexual maturity. So they may have some cones, but probably not very many. Uh huh. So it's kind of, you know, this combination of factors where the post-fire environment is much harsher for regeneration because we're missing this residual forest structure that acted like a canopy. And we're missing a lot of the seed sources that are, you know, essential for the forest to regenerate.

Daniel: So it's kind of like the fire burning a little bit ahead of schedule. Though that may have happened in the past, we don't know quite how often, it's definitely unusual for the past century.

Tyler: Right. So now you're really locked into this trajectory of only the most fire-adapted species can really reestablish in that type of setting. And so what we saw was, you know, the vast majority of our plots were either larch, dominated by larch, or lodgepole pine.

Daniel: So comparing them, the two survey sites, you're swimming through fields of wildflowers on one side, and then on Howe Ridge, are you just baking in the sun?

Tyler: Basically. I mean, it depends where you were, but particularly that south-facing slope of Howe Ridge that you see when you look across Lake MacDonald, you know, that's a south-facing slope. So it's particularly warm and dry. And so that area before 2003, that band along the lakeshore, that was Cedar-Hemlock forest. Hmm. And you can imagine what it's like to walk around in it, in an old-grown Cedar Hemlock forest. It's totally shaded. It's, you know, you have plants that don't even photosynthesize, there's so little sunlight. It's moist, right? Huge old trees.

Daniel: Lots of moss.

Tyler: Yeah. Moss and

Daniel: It's like the Avalanche Creek area

Tyler: It's like Avalanche Creek area. Yeah. So you go from that before 2003 to now, you have a setting where it's super dry, rocky, and it's mostly willow and some aspen, some larch, some Douglas fir seedlings coming back, but really low tree densities, particularly in that area. So I think it's just really striking that in this one particular area, we went from an old growth Cedar-Hemlock forest to a really hot, dry shrub field.

Daniel: Wow.

Tyler: In 20 years.

Daniel: Yeah. Interesting.

Tyler: So it's not that reburns are are everywhere all the time right now. But what makes them so interesting from a science perspective is that we think of them as like this window into the future. Yeah. And so that's why we want to go into those places now and start to understand what's happening. And, you know, the thing with the Cedar-Hemlock forests around Lake MacDonald is those are established centuries ago. Mm hmm. And so not only has there been modern climate change, but, you know, there were fluctuations in climate before the industrial period, and those forests established during what was called the Little Ice Age. So it was a particularly cold period at the end of the Holocene, the last kind of interglacial period.

Daniel: When the park's glaciers were really robust.

Tyler: Right. So that's when those forests established. So they establish in a climate that's really, really different from the climate today. Mm hmm. And so the thing that's cool and fascinating about trees is that they're really long-lived and they're really resilient. So trees can sort of be out of sync with their climate for a pretty long time.

Daniel: Interesting.

Tyler: Right? Because they have these big roots that can access water from a lot of different places. They create their own microclimates. Mm hmm. So the Cedar-Hemlock forests around Lake McDonald have been out of sync with climate for a while. Mm hmm. But what we're seeing is that fire is really catalyzing that change. Mm hmm. Where eventually, if the climate continued on the trajectory that it's on, even in the absence of fire, those Cedar-Hemlock forests may die during a severe drought or something like that. But fire comes through and is really the event that catalyzes that shift in in an abrupt way.

Daniel: Hmm. Can you give me some more details on that? Like what's regrowing? Grass?

Tyler: Yeah, I mean, what that looks like is, right now that landscape is is really dominated by shrubs. It's really open. And in a few decades, it may be like a more open forest that we find really pleasant and desirable. Or it may be that we just have this really prolonged period of recovery, and we may never get a forest recovering in the way that it was before.

Daniel: Hmm. So to some extent, fire re-burning more regularly, burning hotter, more often because of climate change, it's kind of simplifying the landscape a little bit. Whereas historically, traditionally, the wildfire was more of a diversifying agent on the landscape.

Tyler: I think that's a really good way to put it, yeah. And that's what's so hard to grapple with, is that like if we're able to sort of mitigate global climate change, and temperatures sort of plateau, and rates of burning plateau, it's not impossible that the historical forest types that were there can reestablish. But with all those caveats, that would still take, you know, a century to play out and it's -- a century is a long time. For people. You know, it's not so much time for trees, but it is a really long time for people. And so I think sometimes like, us, especially scientists, kind of get hung up on like, well, how permanent is this transition? Like, it's not going to be that way forever. And I think sometimes that's missing the point a little bit. Because it is that way now, and it's going to be that way for the next few decades to centuries. And that's really what matters for us. Right. And yeah, for several generations of people on the landscape.

Daniel: That's what matters for us and for anyone we're ever going to meet.

Tyler: Exactly.

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Daniel: And then I guess if we're making predictions about what Glacier's going to look like 100 years from now, the safest bet is that all of these different things are going to play out in different places. Some places are going to become grassier, some -- it's going to be all of the above, I guess.

Tyler: Exactly.

Daniel: Okay.

Tyler: What that means, though, is that, you know, those are a few different pathways that are all possible and like you said, are are all likely to play out somewhere on the landscape. Mm hmm. What's less and less likely are old forests, and forests dominated by really fire-sensitive species. Mm hmm. So old subalpine, spruce-fir forests, old cedar-hemlock forests, old whitebark pine forests, those are the types of forest that we probably will see less of in Glacier in the future. Or will occupy less of the park than they do now, or than they did in the past.

Daniel: Yeah, maybe this isn't even your job to answer this, but what's the response then? What can we do to adapt to this?

Tyler: I mean, I do think that, yeah, it's not my job to say exactly what we should do. I do think it's my job to try to help to provide information about, this is what we think is happening, and these are the likely scenarios. What we should do about it really depends on what do we value? What do we find desirable, what do we find undesirable? And what are we willing to do? Mm hmm. There's a really useful framework for climate adaptation that was actually developed by the National Park Service Climate Change Response program called RAD: Resist, Accept, Direct. And it's a really useful way to think about, okay, here's where we're headed. And then it helps us to decide, okay, is that where we want to go? And then if it's not, let's think about the options. We can resist -- in Glacier, resistance means when we have a really hot, dry summer and there's a fire in the park, we're going to put sprinklers in Avalanche Creek. Mm hmm. Or we're going to do things like they did in Sequoia and wrap Mylar around precious individual trees. Yeah. Right. That's resisting.

Daniel: Doing everything we can to stop it from burning.

Tyler: Doing everything you can, right? Or or bringing in air tankers and suppressing fires right when they start. Mm hmm. And sort of saying, Yeah, fire -- we know fire is like an important ecological process in Glacier, but we're not really comfortable with the consequences, and so we're going to resist.

Daniel: Mm hmm.

Tyler: Directing might be more like, let's allow certain types of of change to play out, and let's sort of give some nudges or kicks along the way to help the system move in a direction that we find more desirable.

Daniel: Like prescribed burning, maybe.

Tyler: Like prescribed burning, or fuel treatments, or thinning out vegetation to modify fire behavior when it does happen. Mm hmm. Or in the case of like, replanting, maybe we replant with species that are more fire-adapted or more drought-tolerant than what was there before. Instead of just replacing the forest with what exactly what was there before. Right. So that was Direct. And then Acceptance is just saying here in Glacier, we're just going to let things run their course and see what happens. Mm hmm. And just be okay with what that, whatever that is.

Daniel: Yeah. And it could be, you know, in this part of Glacier, in these situations, we accept it. And in this part of Glacier, and in these circumstances, we resist or direct it.

Tyler: Exactly. And so if it looks like we're headed towards a park-like larch forest, we might say, yeah let's accept that. That sounds good. We like, we like hiking through that better than we like hiking through really dense lodgepole pine. Like, maybe that's okay. But when that means, you know, a transition to invasive cheatgrass, maybe that's not acceptable to us anymore.

Daniel: Yeah.

Tyler: I do think it's important to just like, just at least acknowledge, you know, it is hard to watch old growth Cedar Hemlock forest burn. You know, like, even if there are beautiful wildflowers that come up after. Mm hmm. It can be beautiful and fascinating and also sad.

Daniel: Yeah. And it's like, it is a natural part of this ecosystem, and yet it is also increasing in severity due to human-caused climate change. And it is like, a natural thing, and it was also like, toxically unhealthy for our lungs to live in it. [both laugh] Right. Like.

Tyler: Right.

Daniel: It's all of this.

Tyler: Yeah. I mean, I think that's where it adds a lot of complexity to the "what to do about it" as well. Because you can take a perspective that like we're just going to let things play out and be hands off. But the reality is that we are already having an influence on this system. You know, even if we're not out there harvesting trees, you know. And so pretending that we aren't influencing the system is is sort of, I think, a sort of choosing to ignore the influence that we know we're having.

Daniel: That we already have. Not to mention the 10,000 years of history of people intentionally having a lot of influence anyway. So it's like....

Tyler: Right. So I think, you know, it gets tricky and we should be careful about everything we do as, you know, like stewards of a landscape, but, like the context for stewardship is changing really rapidly, and so we might need to get more comfortable with things that we've previously found uncomfortable.

[guitar and drumbeat starts to play]

Daniel: Mmhmm. Well, Dr. Hoecker, thanks for coming in, chatting with me. This has been really, really fascinating.

Tyler: Awesome. Thank you, Headwaters team, for having me. Pleasure to be here.

[hopeful, slightly ambiguous music continues to play]

Peri: Headwaters is funded by donations to the Glacier National Park Conservancy. As an organization dedicated to supporting the park, the Conservancy funds a lot of sustainability initiatives from solar panels on park buildings to storytelling projects like this one. The Conservancy is doing critical work to prevent the worst impacts of climate change. You can learn more about what they do and about how to get involved at Glacier.org. This show is created by Daniel Lombardi, Michael Faist, Gaby Eseverri, and me, Peri Sasnett. We get critical support from Lacy Kowalski, Melissa Sladek, Kristen Friesen, and so many good people with Glacier's, natural and cultural resource teams. Our music was made by the brilliant Frank Waln, and the show's cover art is by our sweet friend Stella Nall. Check out Frank and Stella's work at the links in the show notes. Besides sharing this episode with a friend who might appreciate it, you can help us out by leaving a rating and review in your podcast app. Thanks for listening.