[00:00:08] Speaker A: Good planets are hard to find out. Temperate zones and tropic climbs and thriving seas.
Winds blowing through breathing trees and strong ozone. Say.
[00:00:35] Speaker B: Hello, case Squid listeners. It's every other Sunday again, and you're listening to Sustainability Now, a bi weekly Case Good radio show focused on environment, sustainability, and social justice in the Monterey Bay region, California and the world. I'm your host, Ronie Lipscitz. Sequoias are among the oldest living things on Earth, and most of the world's sequoias are in California, especially Sequoia and King's Canyon national parks. Since 2020, almost 20% of that iconic species has been destroyed by wildfires. The park's management is planning to repopulate the burned over areas with thousands of sequoia seedlings in an effort to rebuild the six groves. But not everyone supports this project. Some ecologists argue that there are enough seedlings growing in those groves to provide the next generation of trees.
My two guests today will address the pros and cons of this project. During the first half of the show, I'll be speaking with Dr. Christy Brigham, chief of resources management and science at the two national parks, who was one of the architects of the plan. During the second half, I'll be talking with Dr. Chad Hansen, cofounder of the John Muir project and a critic of the reseeding plan.
Dr. Christy Grighgam received her doctorate in environmental science and policy from UC Davis in 2001. She's worked for the National Park Service in different parks in California as a scientist and manager for the past 19 years.
Dr. Christy Brigham. Welcome to sustainability. Now.
[00:02:14] Speaker C: Thank you. Thanks for having me on, Ronnie.
[00:02:16] Speaker B: So why don't we begin by having you tell us something about your role and responsibilities as chief of resources, management and science at Sequoia and Kings Canyon national parks.
[00:02:30] Speaker C: Yeah. So I oversee all the science and monitoring that occurs in these parks in support of park decision making, visitor use, so wildlife, plant ecology, mapping, cultural resources, all those kinds of great scientific information that we use to support the decisions that we make here in the parks.
[00:02:54] Speaker B: How did you end up in this position?
[00:02:57] Speaker C: Yeah, I did my PhD at UC Davis, I finished in 2001 in ecology, and I started working in 2003 for the Park Service as a restoration ecologist.
And I've been working as a scientist and a manager for the Park Service ever since, so about 20 years. And I've been here at Sequoia and Kings Canyon in my current job since 2015.
[00:03:26] Speaker B: Okay, so we want to talk about the project to plant Sequoia seedlings right. And burned over groves in the two parks. But why don't we start with having you tell us what exactly is a sequoia? And I know that they need to be distinguished from redwoods right. And what is notable about them.
[00:03:51] Speaker C: Yeah.
Since this is radio, I'm going to both give you some facts as a scientist, but also wax a little poetic so your listeners can have an image.
Giant sequoias are really remarkable as trees. And they are kind of the spokes trees for the rest of the forest.
They're notable because of their size and their age and their personality. So they're these huge red barked trees. They're actually the largest non clonal organism on Earth by volume.
And they are very spectacular when you encounter them in the forest, they're very red. The trunks are fat, the trunks go up 200ft into the air. They have these crazy broccoli tops where they have one big arm and the tops broken off, and they live to be 3000 years old. They're really spectacular. They are closely related to coast redwood, but much more limited in their distribution. So only growing on the western slope of the Sierra Nevada in about 80 groves, covering about 25,000 acres. So not a common tree.
[00:05:09] Speaker B: How many trees does that include then, those 80 groves? Roughly speaking?
[00:05:14] Speaker C: That's a great question, and you would think we would know the answer because they've been of interest to people for so long, but we actually don't know. We think that there's about 75,000 large sequoias, sequoias over 4ft in diameter, which sounds like a lot, but for a tree is not very many.
[00:05:36] Speaker B: And what fraction of those are in the two parks?
[00:05:38] Speaker C: We have about 40% of the area of sequoia groves in the world. In these two parks, distributed in 37.
[00:05:47] Speaker B: Different groves since 2015, I gather, high intensity wildfires have badly damaged many of the sequoia groves. And so could you tell us something about the extent and the impacts of the fires on these groves?
[00:06:01] Speaker C: It has been a very rapid and somewhat startling impact that mainly occurred in just a handful of fire seasons. Giant sequoia are incredibly well adapted to fire. They evolved in an ecosystem that burns regularly. So it's very surprising and unusual to have so many trees killed by wildfire. And we estimate that about 13% to 19% of all large sequoias have been killed in just two fire seasons. The 2020 Castle Fire. And then in 2021, we had the KNP and the Windy fire, and those fires really were burning through areas where we, as land managers, had been suppressing fire for a century. So you had a huge accumulation of dead trees and small diameter trees that would have been removed by more frequent lightning fires. And then the climate change driven hotter drought of 2012 through 2016 really made that worse by killing more trees and really drying out the forest. And that combination of fire suppression and climate change combined to create some wildfire conditions that these trees are not evolved to survive.
[00:07:21] Speaker B: What was the extent of the fire impact on the groves and how many groves were really badly burned?
[00:07:29] Speaker C: Yeah, it brings to light one of the many complexities of thinking about fire and forests. There were a lot of groves that burned, but actually had beneficial effect. The large sequoias were not killed, the fire went through and burned up a lot of the trees that had come in, and probably largely beneficial impact for us here in Sequoia and Kings Canyon. Of our 37 groves, 27 have burned between those two fires. And of those, only portions of six groves are part of this project, where we asked, hey, what happened? Are there so many dead trees and so little natural regeneration that we need to consider replanting?
[00:08:13] Speaker B: So how do Seyas usually regenerate after fires?
[00:08:17] Speaker C: That's part of their evolutionary history with fire. And in the Sierra Nevada, before European occupation and removal of indigenous tribes from these areas, these forests burned quite frequently. And that how frequently depends on the specific forest type. But for giant Sequoia forests, individual groves were probably burning anywhere from about every ten to 20 years. And that was a combination of lightning, we get lots of lightning, storm and also indigenous burning. So tribes were actively stewarding these landscapes to prevent fuel buildup, to care for ethnographic plants, to make better hunting. And so these trees evolved in a frequent fire system. And the way they regenerate is they actually rely on fire to come through and burn all the litter off the ground and create small openings in the canopy by killing a few white fur or incense cedar or maybe a few pines. And then the heat from the fire actually opens these green cones that are held on the living tree. Those seeds fall down on the bare soil and you get very dense, incredibly dense cohorts of little seedlings. They actually rely on fire to create the next generation of sequoias, but from the living adults.
[00:09:48] Speaker B: So let's just say you have an open space, you get fair, you get regeneration with seedlings. What's the survival rate of a cohort hort like that?
[00:09:59] Speaker C: Yeah, we don't have great. I want to be very careful because survivorship is a very specific thing. And to know that you have to mark individuals and record whether they live or die. Right. If we just count seedlings, some could have died, but some new ones could show up. And people have been studying giant sequoias for a long time, since the early 19 hundreds. And so we do know that you get these incredibly dense patches of sequoia regeneration from natural seeds to become seedlings. But most of them, the vast majority of them die within the first five years. And then there's continued mortality year after year, decade after decade, until they become these large old trees that almost that take forever to die, that take 2000, 3000 years. There are some estimates that the mortality of seedlings in the first season with a drought might be as high as 90%. So really dense seedlings. And the thinking is the trees produce that much seed because a lot of them are going to die. They're not big, the seeds are very tiny. Nature is a harsh environment, so most.
[00:11:15] Speaker B: Of them die now tell us about the project, the replanting project, and what that entails.
[00:11:22] Speaker C: The replanting project was really born out of a question. When the 2020 castle fire burned through a handful of groves in the park, about eleven sequoia groves. In one of those groves at the time, it was burning large chunks of needles that are 200ft off the ground in a big sequoia, were blowing and landing on the ground in three rivers. And when we saw that thought, wow, something unusual is happening. Normally in a wildfire fire does not get into the crown of a sequoia. It doesn't get into the needles. They're so far off the ground. So then we started to get drone imagery and satellite imagery, and some of these groves board Camp Homer's, Nose, those are specific areas near the south fork of the Kuya River that have sequoias. It looked like most of the large sequoias were killed and were killed by fire actually incinerating burning up the canopy. So not from a heat pulse, but actually fire burning it up. So we started working with USGS collaborators, some partners from UC Davis, to go out to these places and ask how many of the large sequoias are dead, because we know that the adults have the cones that make the new seedlings. Are there adult trees left to make new trees? So how many adults are dead and then how many seedlings are there on the ground? Because we've had lots of prescribed fire in our park and we've had some previous wildfires in sequoia groves, we've never had to replant. The trees have always survived. There have been reproduction. And we did those studies for two years, counting seedlings and looking at mortality of adults with these partners that I mentioned from UC Davis and USGS. And what we found was that in these areas of what we call high severity, where the fire burned very hot and removed 75% to 100% of the canopy, that 90% or more of the large sequoias are dead. There aren't cones left, and there aren't adult sequoias left to make seedlings in the future. So any seedlings that you have or don't have on the ground, that's your future grove. We also measured the seedlings, and the hard part there is because we know they produce lots of seedlings, it raises the question of how many seedlings are enough to recreate a resilient sequoia population, adult sequoias that can make cones and repopulate after the next fire.
And our conclusion, based on a lot of research and analysis and work with some of the best sequoia researchers in the world, like Dr. Nate Stevenson, is that these areas that burned at high severity do not have enough natural regeneration to reestablish a sustainable sequoia population. And that's why we are proposing and are actively replanting seedlings in some areas.
[00:14:54] Speaker B: Couple of questions.
If you didn't do this, what would be the result around these groves? I mean, what would be the succession ecology, I guess.
[00:15:04] Speaker C: Ronnie, like so many things in life and science, there is uncertainty. Okay. I don't have a time machine. I wish I did. But the probabilistic modeling that USGS did for US, based on what we've seen in past prescribed fires, indicates that there is a high likelihood that these areas that have pretty low natural regeneration would not be sequoia forest, that they would become shrub dominated. And there's a lot of emerging research. There's three different papers that have just come out in the past couple of years that areas that burn at high severity, they tend to reburn at high severity, and that potentially provides even further impact to the groves. That the areas that didn't burn at high severity because you're bringing more fire into those groves. So our conclusion was that there was a substantial risk that much of these areas would be converted to native shrubs and would no longer be Sequoia Grove.
[00:16:12] Speaker B: I'm curious. Was the extent of the Sequoia groves greater in the past, as far as you are aware?
[00:16:19] Speaker C: Yeah. And certainly the spatial extent of Sequoias and their evolutionary relatives, maybe from a lot of those fossils, it's hard to tell exactly, but the Sequoia's ancestors and the redwoods ancestors were certainly more widely distributed in the past when it was cooler, and they've undergone both constrictions and then expansion within geologic time. But that's a very different timescale than wiping out 19% of all large trees into wildfires driven by fire suppression and climate change.
[00:16:56] Speaker B: I'm going to ask a hypothetical question here. All else being equal, if there wasn't a human presence in this area or in California or whatever, would the Sequoia groves have? Were there signs that the extent was decreasing?
[00:17:13] Speaker C: No. So in the most recent past, the groves have actually been expanding their area, looking at pollen records from Tulari Lake, from maybe having been more restricted to smaller, wetter riparian areas when, in the cooler period, they've expanded into their current footprint. And some of the work that Dr. Nate Stevenson has done and others have done indicate that certainly for some of the groves in Sequoia and Kings Canyon that have prescribed fire, that those appear to be stable populations. So they don't show signs in our short human lifespans of expanding, but they also don't show signs of contracting either.
[00:17:59] Speaker B: All right, so what's the pattern of planting the seedlings? How does that work?
I assume this is underway now, right?
[00:18:08] Speaker C: Yes, it's underway in two out of the six groves.
[00:18:12] Speaker D: Okay.
[00:18:12] Speaker C: Board, Camp and Redwood Mountain Grove cones were collected primarily for 80% of the cones came from the local genetic neighborhood. So either the grove itself or groves that are connected by pollen and those cones were collected. The cones were dried. The seed was extracted. It was cold, stratified, and then it was grown in nurseries, three different nurseries here in California. 20% of the material actually comes from groves that are large. So have more genetic diversity or some groves that are hotter and drier. And that 20% was determined from advice and papers around how to increase genetic diversity under a changing environment so that evolution has a larger palate to act on. And that's called assisted gene flow. So we have these seedlings, they're about six inches tall and they have about six to eight inches of roots. And individuals, they were carried in Redwood Mountain Grove by mules down into the grove. And then planters are using a tool called a ho dad to plant them by hand. They're being planted in a pattern that's called individuals clumps and openings that is meant to mimic the natural pattern of regeneration where you get small clumps of trees and then one by itself and then some open space in between and that's what's happening.
[00:19:57] Speaker B: What's the time frame then for all of this? Not for the planting, but I mean to be able to judge whether it's successful or not. Right. We're talking about some extended time period. What would that be? Ten years, 20 years? More?
[00:20:11] Speaker C: That is such a good question and I'm glad you asked it because it's one of the aspects of working with giant sequoias that I really appreciate. This is the longest of the long games, Ronnie. These trees, there actually is not good data on how long they take to even make one viable cone. Could be as many as 30 years. The evidence from a couple of different published studies in terms of how many cones are on a tree and because so many of the seeds die is that you need about 400 to 1000 year old trees to make a population that replaces itself. I'm hoping that when I'm 51, I'm hoping that when I'm 81 I'll be able to hike back down into Redwood Canyon and see some pretty big sequoias that are well distributed and have survived a couple of fires. But it's going to be not my children's children, but their children that determine whether the project has successfully reestablished a self regenerating sequoia grove in these areas.
[00:21:24] Speaker B: So a lot of this is based on faith, right. Hope and faith, I guess. Right.
[00:21:29] Speaker C: And ecology. Right.
[00:21:30] Speaker B: And ecology, of course. I didn't mean to exclude that. So there's this growing movement to assist various species in moving in response to climate change. And I'm curious, is that something that you're taking into consideration?
[00:21:48] Speaker C: It's not something we're doing. So we are moving genetic material assisted gene flow like we talked about. We're not moving sequoias outside of their current range and we don't have any plans in place to evaluate that assisted migration. But I would say that current NPS policy sets up a framework to have those discussions to ask, why would you do this? Do you think a species will persist if you do it? What are the potential implications for the community that you're putting the species in? What are the potential implications for the community that you're removing the species from. And I think it gets at those questions about stewardship. And what does stewardship mean in our modern era?
[00:22:45] Speaker B: Yes, it certainly does. Well, we're almost out of time, and I was wondering if there was anything else you'd like to add to our conversation.
[00:22:54] Speaker C: Yeah, there's two quick things I would love the opportunity to add, Ronnie. The first is that when we talk about wilderness, and one of the controversial aspects of this project is that these groves occur in wilderness. And that's part of the reason why they haven't had a lot of prescribed fire is because it's very difficult to execute in wilderness. And when we think about wilderness and whether humans have a role to play in wilderness management, I think we need to think about two things. One, we've talked about, which is that these landscapes were stewarded by indigenous people for millennia. So consider them a place that has no role. For humans. To be stewards, I think is incorrect. And then the second piece is that they're also not untouched. In every grove that we're looking at, we have suppressed at least 50 lightning, cause fires. So we have taken an active hand, and we are part of why this happened. And so that asks you to ask the question, should we be part of the solution? Can we be part of the solution? So I think that's a philosophical question, and there's many different answers to that, which is perfectly fine. The other quick point I want to make is that we did not take this intervention lightly. We spent two years consulting with multiple experts outside of the Park Service in these fields. We evaluated strongly the potential impacts of planting. 12 million conifers are planted every year in California. Sequoias have been planted all over the place with no detrimental effects. We see no evidence for pathogen introduction. I've talked to tons of foresters and looked at the literature, and we definitely were very concerned about, is this the minimum requirement to maintain the natural character of wilderness, the wilderness character of this area, and to meet our enabling legislation, the purpose of these parks to preserve giant sequoias in perpetuity. And I think if people are concerned and if they read the documents, they'll see that it's a very thoughtful analysis and a very thoughtful process. We may not all agree, and that's totally fine, but we took this decision very seriously.
[00:25:17] Speaker B: Can our listeners find those documents on the park website?
[00:25:21] Speaker C: Yeah, they're on, actually, the planning environment and public comment website, which I can never remember. So if you just Google replanting giant Sequoias, sequoia, Kings Canyon, it should come up.
[00:25:34] Speaker B: Okay, well, Dr. Brigham, thank you so much for being my guest on Sustainability Now.
[00:25:39] Speaker C: Thank you, Ronnie. And thanks for talking about this important topic.
[00:25:43] Speaker B: You're listening to Sustainability now? Our topic today is a project underway in Sequoia and Kings Canyon National parks to restore burned over groves of giant sequoias. You've heard my first guest today, Dr. Christy Brigham, chief of Resources, management and Science at the two national parks. My second guest is Dr. Chad Hansen, director and principal ecologist at the John Muir Project at the Earth Island Institute, which he co founded in 1996. Dr. Chad Hansen. Welcome to Sustainability now.
[00:26:18] Speaker D: Thank you.
[00:26:20] Speaker B: Why don't we begin by having you tell us about your background, your role at the John Muir Project, and what the John Muir Project does.
[00:26:28] Speaker D: Sure. Well, John Muir project. I'll start with that. John Muir Project is a small forest conservation and research organization. We do original scientific research on forest and fire ecology. We do public education work, and we also enforce federal environmental laws on federal public lands when the science is ignored or misrepresented by federal land agencies.
As far as I go, I've got a PhD in ecology from the University of California at Davis, and my research field is Forest and Fire Ecology. I've published about 50 peer reviewed studies in scientific journals around the country and around the world and written two books, third in the works. Mostly I'm a field ecologist, so I'm a boots on the ground guy.
[00:27:11] Speaker B: Your research is focused, among other things, on regeneration of post wildfire forest ecosystems right. And species response to wildfires. So can you tell us about the role of wildfire and sustaining forest ecosystems?
[00:27:27] Speaker D: There's a lot of understanding now about the importance of low intensity surface fire in forest ecosystems. A lot of people get that. But a lot of people think of the value of low intensity surface fires as in kind of reducing the pine needles and twigs and dry leaves on the forest floor and keeping the kind of accumulations of saplings down, and therefore that it might prevent a high intensity fire from occurring. The reality is ecologically, and we understand so much more now than we used to about these ecosystems. Some species have evolved to really prefer a very dense forest, very high canopy cover, where mostly low intensity fire has occurred, or it hasn't burned in a long time. Other species are on the opposite end of the spectrum. Some like it hot. They like those patches where the wind really flares up, kicks up, and the flames go high, and it's a hot, dry, windy period of time, and the fire kills most or all the trees in that patch. We used to have very little understanding about that, but now there's hundreds of scientific studies on that subject. And what basically we understand now is that many species have evolved to depend on those patches that burn hot. We call it snag forest habitat, also known as complex early cereal forest. And it turns out that it's comparable to old growth forest in terms of native biodiversity and wildlife abundance. So contrary to being destroyed like we used to think, these areas are ecological treasures.
[00:28:59] Speaker B: What kind of species live in these places where they're high intensity fires?
[00:29:05] Speaker D: Yeah, a lot of them. Well, one I've been studying for about 20 years now in the field is the blackback woodpecker. That's one of the most iconic ones that was really strongly, strongly associated with large patches of very dense, mature forests that burn hot. And the reason is that blackback woodpeckers have evolved to depend on the larvae of woodboring beetles as their food source. And wood boring beetles are native beetle species. There are dozens of them. And they have evolved to depend on patches of high intensity fire. Basically, they need recently killed trees, fire killed trees in order to reproduce. And so these beetles have evolved receptors in their bodies to detect fire by heat or by smoke, depending on the species. And they will fly toward the fire and colonize an area right after the flames have passed and after the firekilled trees have started to cool. But literally while the smoke is still hanging in the air and they'll lay their eggs on the charred bark of a firekilled tree, the larvae will develop and bore through that charred bark into the wood of the tree. And they develop over the course of time into adults. And then they emerge. They'll go through another cycle or two in that same area until they look for a new fire. But while they're in those trees, those firekilled trees, what we call snags, or if you're Australian fire ecologist, you call them stags, which I kind of like that term better.
The larvae is the food source for these woodpeckers, and not just the blackback woodpeckers, many different woodpecker species. But just to put in perspective, the blackback woodpecker is so dependent on this one, blackback woodpecker will eat about 13,500 of these wood boring beetle larvae every single year. And so they need a lot of firekilled trees, but it doesn't end there. This is really cool. So the firekilled trees are not just a food source for the woodpeckers and lots of other species, too. But dead trees are softer than live trees. And so it allows the woodpeckers, it makes it easier for them to excavate nest cavities in those dead trees. And the blackbacks, they're monogamous species, like most of the species in their genus, and they excavate nest cavities, usually about three per year. And they pick the one they like the best every spring. And the ones that they don't choose or the ones from the previous year, those are available to all the other cavity nesting species in the forest that have to have tree cavities to raise their young and reproduce every year, but are not able to create their own. Bluebirds nut hatches, flying squirrels, chipmunks. Dozens and dozens and dozens of bird and small mammal species need these nest cavities, and they rely on blackbag woodpeckers and some other related species like hairy woodpeckers, to create them for them.
You have this rich interconnected system then, of course, the really intense fire, those high intensity fire patches, they stimulate the reproduction of these native shrubs that you may only see once every couple of hundred years in a given area to any significant degree. They require high intensity fire. And those native shrubs are flowering species. And so they proliferate after intense fire in patches. And that attracts native flying insects and that provides food for fly catching birds and bats and the shrubs, and then the snags when they fall those down logs, that is prime habitat for small mammals and shrub nesting birds like wood warblers in particular. And so even a lot of the species that we've always thought of as old growth species like spotted owls, like Pacific fishers, well, it's true, they do really depend on mature and old growth dense forest for nesting or for denning. But they go out of their way to forage in the Snag forest habitat because the small mammal prey biomass is two to six times higher in Snag forest than it is in unburned or lightly burned old forest. And so we call this the bed and breakfast effect. Turns out they need both.
[00:33:04] Speaker B: That's really interesting.
When you have these high intensity fires, does the original forest regenerate or it does, yeah.
[00:33:15] Speaker D: This is one of the biggest myths out there, this idea that these forests are not regenerating. One of the things that I do as a field ecologist is take people out to these areas and show them myself, because I don't want people just to take my word for it. I mean, I do the field research, I publish the studies based on actual field data. But the studies that people hear about in the press that say, oh, well, these forests are not regenerating after fires, most of these are theoretical modeling studies. These are done by folks in their offices using algorithms, and these are folks who are not even getting to booth dirty. So if you go to the areas, what you will find and it doesn't always regenerate in the first year after fire, that's a myth too. Whatever you have at one year post fire is all you're ever going to have. It takes some time sometimes, yeah.
[00:34:03] Speaker B: How long does it take?
[00:34:04] Speaker D: Well, in some areas in these high intensity fire patches, you'll see thousands of seedlings per acre in the first year post fire. Some areas you'll see hundreds per acre in the first year post fire. Other areas you'll see nothing at all at one year post fire, nothing at two years post fire, nothing at three years post fire. Then at four years post fire, all of a sudden you got 300 per acre. It really is interesting. And of course, it's not just the conifers. It's also the oaks and the dogwoods and all the other tree species and the native shrubs. The conifers are only part of the ecosystem. But I've been doing this work, focusing in the field as. A boots on the ground field ecologist, primarily researching large high intensity fire patches for over two decades. And I have yet to find a single hectare of forest. Hectare is about two and a half acres. I've yet to find a single hectare that has not regenerated. And a lot of this regeneration is happening during drought cycles. Forests regenerate during droughts, too. They regenerate better when there's a lot more moisture, but you tend to get more pines during the droughts and maybe more fur and cedar during the wetter periods. But it's a myth that our forests are not regenerated after fires. That is an absolute myth.
[00:35:17] Speaker B: I want to ask you about the modeling, because obviously the modeling is based on some kind of data, right? And not just simply on, I don't know, imaginary algorithm. Just looking at some of the research, it's hard for a non ecologist to read in terms of trying to figure out what's going on. But clearly something has to go in to the model. What about that data? I mean, how is that collected?
[00:35:42] Speaker D: Well, it's interesting. So one recent study, they use field data to create a model. And some models, by the way, are imaginary entirely. There's literally no field data whatsoever. It's entirely hypothetical modeling assumptions. And those get published. They probably shouldn't, but they do. But this particular study did use field data, and quite a lot of it, actually.
But then they said, well, they're never going to create a model that says, well, let's assume that great majority of the landscape burns in very, very large high intensity fire patches. And let's assume, and then add to the assumptions, assume this, assume this, assume this, and making increasingly disfavorable assumptions to regeneration. And then if we assume that, if we assume most of the landscape is like that, oh my gosh, we're not going to have hardly any regeneration. But again, that's based upon a series of hypothetical assumptions that are divorced from reality, whereas the actual field data are very, very different. And if you just focus on what we actually have, you find that it's very, very different from what most people think. So first of all, even the biggest fires are mostly low and moderate intensity. And so you have primarily live, surviving mature trees. They're scorched, but they're live and surviving only a minor portion, significant, but minor portion is high intensity in our forests even. Doesn't matter how big the fire is. That's what we have. That's on average, right? You can have some variability, but it typically averages between 2020 5% or so of a given fire, even really big ones. And so those are the high intensity fire areas. Now, a lot of those high intensity fire patches are really small and you've got live trees all around them and scattered throughout them, and you've got some bigger patches.
And the question is, well, what do you find in those bigger patches? But the main thing to understand is that even those big high intensity fire patches, the interior areas of those big high intensity fire patches that are far from live trees, is a small fraction of 1% of the forested landscape. It's a really small, small portion of the forest landscape. And that's where all the focus is right now. I think a lot of people have this idea that most of our forests are in these large, high intensity fire patches. And that's also mythology. It's a really small percentage. But even so, it's important to understand that because we have got more fire now than we had 20 years ago. And so I've been focusing on my research on that fraction of 1%, and it turns out we've got lots of regeneration there, even 300 meters from the nearest surviving live tree. And this is what's wrong with those models, is that they make the assumption that a forest won't regenerate if it's more than a certain distance from a live, surviving tree. Maybe 100 meters, maybe 200 meters. I'm finding regeneration 300, 400, 500 meters away from the nearest surviving tree. And those areas are very rare, again, spatially, but they happen. And so it makes sense to people that it couldn't possibly regenerate if the live trees, that seed source is too far away. They forget that a forest forest is an ecosystem. It's not just a collection of trees. It's also birds and small mammals. And it has been for millions and millions of years. And a lot of these birds and small mammals spread seeds all over the forest at any live tree. In fact, they've been recorded spreading seeds as much as 14 km from a live tree.
[00:38:58] Speaker B: Wow. Well, so let's get to the sequoia replanting project, because after all, that's why we're here. You've criticized it as a terrible idea. Why do you say that? And of course there's also this whole question about how badly burned are the sequoia groves. But first of all, why do you think it's a terrible idea?
[00:39:18] Speaker D: Well, it's a terrible idea because the National Park Service has not been honest with the public about the extent of natural sequoia regeneration in the high intensity fire areas. They've been misleading the press and the public to a rather spectacular degree. And I'm saying that very, very bluntly because it needs to be said bluntly. The sequoia regeneration is by far the highest in the high intensity fire areas. It is growing by far the fastest. It is most dominant.
And not only that, in the high intensity fire areas, based on the park's own data, the sequoia regeneration is significantly higher than their reference data that they typically use. And they've been implying to the public that it's much lower, perhaps just a fraction of what they would typically see. That is highly misleading. And I explain why and how they misled the public, if you're interested.
[00:40:08] Speaker B: Oh, yeah, sure.
[00:40:10] Speaker D: Okay. The giant sequoia is a serotoninous species and what that means is serotoninous trees around the world are trees that have evolved to depend on high intensity fire in particular to effectively reproduce.
And when they have high intensity fire they often reproduce in dramatic fashion. And giant sequoias need three things to effectively reproduce. They need fire that burns hot enough to release seeds from the cones but you can get that with moderate intensity fire and even at the upper end of low intensity you'll get seed release, not very low intensity, but kind of at the cusp of low and moderate you'll get some seed release. But they need that. They need fire to consume the thick duff and litter on the forest floor and turn it into a nutrient rich bed of mineral ash. The duff and litter, pine needles, decomposing leaves and twigs that material on the forest floor in a sequoia grove is extremely thick, some of the thickest of any forest ecosystem on the planet. Basically, if the seedlings germinate in duff and litter they're not sinking the roots into soil, they're sinking it into duff and litter which can't really sustain them, they'll die. And so they need the fire to consume that duff and litter, turn it into a bed of mineral ash so the seedlings can sink their roots into soil and have all those nutrients to spur their growth for many decades to come. And the third thing they need is for fire to burn intensely enough to kill most of the forest canopy so they have lots of sunlight in those first few years that they're growing in particular. If they have all three of those things, they thrive and they will do that in a small high intensity fire patch. And they will do that in a very large high intensity fire patch. I'm finding some of the highest sequoia reproduction in areas that are 300 hundred, 4 meters away from the nearest live mature sequoia and again, those areas are very rare. Just to put in perspective, in the recent fires that have burned through sequoia groves, almost all of which have been natural lightning fires by the way, it's been 87% low and moderate intensity where the mature trees get scorched but generally not killed. Small amount of mortality in moderate, but not that much. Most of the tree mortality is in high intensity but it's even still it doesn't kill all of the mature sequoias. A lot of the big ones survive just fine and a lot of the ones the mortality of mature sequoias, by the way, this is another thing the park has not been honest with the public about. They've been telling the public, and it's been repeated in the press again and again that 20% of mature sequoias, of all mature sequoias in existence have been killed in recent fires. That's not true. That was not based on any peer reviewed study, it was based on subjectively chosen data and a lot of the trees that they assumed were dead are not dead here's. The problem with sequoias is that they look dead initially, but unless you come back year after year and really scrutinize them, you will not realize that a lot of the ones that look dead are actually not. They start to produce new green foliage from the very top of the crown. Bright new green, fast growing foliage. It just goes up and up and up and up. That oftentimes you can't see at year one or even year two post fire from the ground, because the crowns are 200 and 6280ft above the ground in these giant sequoias. So yes, mature, I mean, high intensity fire will kill the majority of mature sequoias, but a lot of them do survive. But when you have high intensity fire, that's a relatively small percentage of the total fire area. What you end up with is a situation where you have relatively minor mortality of mature sequoias and a dramatic reproduction, hundreds and hundreds of new young sequoias growing for everyone that was killed, or even thousands.
[00:43:48] Speaker B: So why has the Park Service I mean, you claim the Park Service has misled the public.
[00:43:53] Speaker D: Yeah.
[00:43:54] Speaker B: So what's it up to?
[00:43:55] Speaker D: Yeah, I don't want to speculate about motives. I will say that there's been a pattern here of Park Service and the Forest Service under the Trump administration is when it started, but it's actually gotten even worse under the Biden administration. There's been a recent pattern of agencies trying to find ways to justify interventions into wilderness areas. This is a really dangerous thing and it's taken a number of different forms, but we're seeing a pervasive pattern across the west in particular, and this is part of that pattern. But let me just explain one thing I think is really, really important here about why exactly how the nuts and bolts of how the park misled the public on this. They took a data set based on a couple of dozen prescribed fires over recent decades, and they looked at the density of sequoia regeneration after those, I think it was like 28 prescribed fires. And they said, oh, well, look at two years post fire, we have an average of 14,112 sequoia seedlings per acre. And so that's what they told the public average was. There's actually two key things where they misled the public. They said, number one, that must be like our threshold that we should shoot for 14,112. The problem is they had 37 different locations where they did these samplings. Only five of them had really, really high sequoia seedling density. The rest were really pretty low for the most part, and many of them had none at all. But five out of 37 were extremely high, and so it threw off the average. And this is the problem with a serotonous species like the giant sequoia. You never use averages. It's highly misleading. It's like, imagine a billionaire acquiring a business, a company with 1000 workers, and then telling the press, hey, I do right by my workers.
The average annual income at my company is over a million dollars a year.
[00:45:48] Speaker B: Right?
[00:45:49] Speaker D: Well, that's technically true. It's also wildly misleading to the point of outright dishonesty. And that's what the park did here. So, for example, in their reference data set, the 14,112 per acre at two years post fire, okay, their reference data set, only 59% of their locations actually had any sequoia reproduction whatsoever. In stark contrast, their own data in the high intensity fire areas, the big high intensity fire patch in the Redwood Mountain grove where they're planting right now. Before they started planting, they found that 100% of these sample locations had sequoia regeneration. 100%? It varied wildly. The lowest was about a dozen per acre. That went up from there to hundreds per acre and then thousands per acre and then tens of thousands per acre. And the point is that their average in their reference data set was higher because of those five out of 37 plots, mostly one one had over half a million per acre. I'm sorry, over half a million per hectare, but over 200,000 per acre. Huge density. And it basically just threw off the average to its dramatic degree. But the point is that when we actually ran statistics on this, which I did, we found that the current two year post fire sequoia seedling density in the Redwood Mountain grove where the park is telling the public it's lacking and is planting right now. That density is significantly higher than their reference density because the great majority of the plots have a lot more sequoia seedlings than the great majority of their reference plots. And so it's just like that billionaire with a company of 1000 employees. Okay, but that's the point, right?
It's like that old saying, there's lies, there's damn lies, and then there's statistics.
[00:47:43] Speaker B: Right?
[00:47:44] Speaker D: And obviously we need statistics, right? Of course we need statistics. But they can be manipulated to the point of dishonesty in ways that the average layperson will not perceive unless they have some explanation.
[00:47:59] Speaker B: Well, listen, I'm afraid we're out of time, but this has really been a fascinating conversation or at least presentation. And I want to thank you very much, Chad Hansen, for being my guest on Sustainability Now.
[00:48:12] Speaker D: Yeah, my pleasure. And I'm happy to do it again in the future.
[00:48:15] Speaker B: If you'd like to listen to previous shows, you can find
[email protected] slash Sustainabilitynow, as well as Spotify, Google Podcasts and PocketCasts, among other podcast sites. So thanks for listening and thanks to all the staff and volunteers who make Case Good your community radio station and keep it going. And so, until next, every other Sunday, sustainability now.
[00:48:47] Speaker A: Good planets are hard temperate zones and tropic climbs and thriving seas?
Winds blowing through breathing trees and strong ozone safe sunshine?
Good planets are hard to find. Yeah, it good.
