Regime Change: History of Fire Ecology in Nevada

From the Ponderosa Pine-covered mountains in the Great Basin to the arid Mojave Desert and all the sagebrush and grass in between, Nevada’s ecosystems are diverse and fire behaves differently across these regions, both historically and today. The guests on the latest episode of the Living With Fire Podcast “Regime Change: History of fire ecology in Nevada,” explain why fire is an important process in Nevada, how scientists study fire, and why understanding the history of fire can give scientists and land managers useful clues to help them manage landscapes today.

Guests:

• Alexandra Urza, research ecologist with the U.S. Forest Service
• Stanley G. Kitchen, research botanist with the U.S. Forest Service
• Matthew Brooks, supervisory research ecologist with the Western Ecological Research Center

Transcript

Megan Kay: 0:19

Welcome to the living with fire Podcast, where we share stories and resources to help you live more safely with wildfire. Hi, I'm Megan Kay, your host and outreach coordinator for the living the fire program. On this episode, we are going to do a deep dive into fire ecology in Nevada. We talked to some fire ecologist who are experts in different ecosystems found in Nevada and also just in the western United States. We wanted to get into the science, we wanted to understand how fire affects these different ecosystems historically and today. So enjoy the episode.

Christina Restaino: 0:59

I'm Christina Restaino. I'm the director of the program and on the faculty at at UNR. I specialize in wildland fire, drought, forestry impacts on on terrestrial ecosystems in the West. I used to work more in the forest ecosystems but learning more about the sagebrush ecosystems and the range land ecosystems of the West now that I have my new position at usr so I've been here since August 2019. So still relatively new. So excited to hear from you guys.

Megan Kay: 1:52

And to give you a little bit of background on me, I, I am a I studied art, fine arts, you know, like I studied printmaking and book arts. And so I'm a liberal liberal arts person, but I did spend five years working as wildland firefighter for NDF, and then also North Lake Tahoe fire. So I have a little bit of background in the ecology just from what I was taught when I was doing treatment, fuel treatments and everything. So I'm kind of that I think Christina pointed out last interview, I'm like the straight man, you know, I'm a person who will probably like challenge you on terms and kind of unpack any sort of rhetoric. So if I slow you down or interrupt you to explain anything, don't be offended. It's just me trying to understand and I you know, I've done research and I've read your guys's work, so I have a good idea of what's going on.

Ali Urza: 2:45

So, I'm Ali Urza. I'm a research ecologist with the Rocky Mountain Research Station, which is a in the research arm of the US Forest Service. I'm based out of Reno, Nevada, and I consider myself a plant community ecologist. I'm especially interested in the drivers of vegetation patterns and change. And a lot of my research focuses in the Great Basin, largely in Nevada, at least for the last, oh, six or seven years or so I've been largely focused in the Nevada portion of the Great Basin. I study the ways that plant communities and ecosystems respond to fire and climate change and other drivers like invasive species. I guess I don't remember exactly how you phrased the question, but kind of how, what interests me or what kind of drives me in this regard. I grew up in Nevada, I actually grew up in Reno and I left for a long time. And I feel just super excited to be able to be back in this area. This is definitely kind of the Great Basin is like my soul region. I think it's a very underappreciated, but magnificent landscape. And it's personally challenging to see a lot of the stressors and changes happening in real time in the Great Basin. And I think that observation of ongoing changes really motivates my work. And I just love having the opportunity to be able to work in the field in particular in these great landscapes. So.

Megan Kay: 4:29

And that was exactly what I was asking. So we'll do, Matt, next, introduce yourself and talk a little bit about what interests you about what you do, and maybe anything exciting that you're working on right now.

Matt Brooks: 4:42

Matt Brooks, I'm a supervisory research ecologist for the US Geological Survey, Western Ecological Research Center in at the Yosemite Field Station. I'm the PI there. I've been working on fire since 89 when I was the Masters student and most of my work has been in the hot deserts, mostly the Mojave Desert. Ali mentioned the Great Basin might be under appreciated, I would submit Mojave might be even less appreciated, especially a standpoint of fire. And so one of the things that's drawn me to working on fire in the Mojave is that because of its infrequency, even compared to the Great Basin and it's there hasn't been nearly as much work done in the in the Mojave as in the Great Basin. And today, there's fewer people working on fire in the Mojave Desert in the Great Basin by quite a few. And so although oftentimes I'm asked to talk about fire in the Great Basin, and I do my best, I'm my expertise is really in the Mojave. And so in this podcast, that's probably where most what I can contribute the most. Now, you might ask why, someone at the Yosemite field station is working in the Mojave, I do other things too. I work on Yosemite toads and mountain yellow legged frogs among other things. And so as an ecologist we do we're asked to do a lot of things and as a federal ecologist is as you know, we all know there's lots of different things that often science is needed for and and so that's what got me in some of these other topics, I bet at the assembly Field Station since 2007. And Previous to that, I was in Southern Nevada at the Henderson field or Las Vegas Field Office of USGS. Probably the niche I have to other than desert fire Mojave Desert fire has been interaction between invasive species and fire. And so I've done work with things like salt, cedar and riparian systems and other species than non native grasses, mustards that sort of thing. And I'm still here still doing it and then working for us well, it was natural biological survey and actually going back quite a ways I started working for the federal government and sort of on contract right after this right after the Babbitt administration and NBS was formed and I was I've been a full time Research Scientist since 98.

Megan Kay: 7:33

So then we move on to Stanley Kitchen if Could you introduce yourself and tell us what interests you about your field of study

Stanley Kitchen: 7:40

Stan Kitchen I'm with the the Rocky Mountain Research Station like Ali only on the other side of the Great Basin in in my my office as rarely as I see it nowadays with with COVID, lockouts or whatever we want to call it is in Provo, Utah. I'm a, as I said, a research botanist and so maybe a little bit different angle on things in that I'm very much interested in the interaction of, of plant communities and disturbance, fire being one of those disturbances, but grazing or, or climate, drought or a number of different other kinds of disturbances can be important as well. And, and I'm interested in the whole plant community how that adjusts to or interacts with disturbance, but also individual species, how they're adapted for, for those disturbance, events, or patterns of disturbance so that they can continue to persist on landscape. I have found a real niche or interest in looking in historical patterns, we can if we can find ways to uncover or, or open up understanding to the past, it can tell us a lot in our present, or about our present circumstances, without having to wait as long periods of time. So I like that intersection between between history or natural history and science and and, and then trying to figure out how we can unpack that for for, for things that are happening in the world today that that makes sense for us. So that's been been my career and I work in the gray basin as well as in other parts of Utah in the Intermountain West, primarily Nevada and Utah. Then a little bit of work in Idaho and other areas as well.

Megan Kay: 9:48

Awesome, and that's why I reached out to all of you guys is kind of to understand the history of fire in these very different ecosystems in Nevada. Like you mentioned, Matt, like the Mojave is very different than the Great Basin. And even within the Great Basin, there's like a huge variety. So thank you guys for all introducing yourselves. I'm even more excited to talk to you. I doing research on this podcast, a term that kind of that is that I guess it's a common term in in ecology and fire ecology, but it's something that I noticed. And as someone who's doesn't have an ecology background, helps me understand this topic. And that term is fire regime. You guys all have it appears in a lot of your guys's research. And so I wanted to quickly unpack that term a little bit and talk about what is a fire regime? And what, how we use it to understand fire behavior, and how we use it to study the history of fire. So I'm going to kind of you guys can raise your hand Who wants to go first? But I don't have anyone in mind who wants to address this first. But who? Yeah, let's just talk about what a fire regime is. So Stan, why don't you go first?

Stanley Kitchen: 11:05

Sure, I'd be happy to first of all, I'd like to, to use a quote from Cecil frost that I think really establishes an understanding he at this quote I've used a number of times, he says, It is now apparent that fire once played a role in shaping all but the wettest, the most arid, or the most the most fire shelter plant communities in the United States. And I would add to that, that fire has been a part of vegetation. Almost since plants emerged and began growing on dry land. The coal records and other records make it very clear, especially during periods of time, when we had high oxygen levels, when even wet vegetation with burn that plants have been kind of adjusting in evolving and adapting to fire as a part of their environment for a very long time. So that's Fire, fire regime, we usually break down into, we'll describe a fire regime based not on one fire. And one fire doesn't tell us much about a fire regime. But but but how we describe a fire regime in terms of patterns of fire patterns to time, patterns across space. And, and, and some some other factors, for example, that patterns that might be important in a fire regime or the frequency of fire, how often might have fire returned to the same place on landscape? Or what season of the year that fire would occur? That's, that's also part of the temporal or portion of a fire regime. And connected to that is the regularity of fire? Is it something that's almost on a regular pattern? Is it synchronized with drought? Or some other factor? Is there some way that that and that that's non fire related, but it's certainly important? The spatial pattern of fire is also important as our fires large? Are they small? Are they continuous? Are they patchy? All of those are important portion of this thing we call fire regime. And finally, there's things like fire intensity, how hot does a fire burn? How long does it burn off? Or how severe is a fire? how large of an impact might it have on the on the vegetation in our landscape? That would generally what we refer to as severity, and then sometimes a portion of of fire regime is, is it a human caused fire regime with human ignitions are Native Americans here but all hunter gatherer societies across the world through time of use fire is a very important tool. So human fire regimes versus natural fire regimes, which except for a few places, where you have volcanoes, it means lightning are are another way of describing or getting at this, this idea of what's the pattern of fire through space in through time on a landscape. And all of those factors, that temporal factors, the spatial factors, and the other factors interact. So if you have frequent fires, more likely to be low severity or low intensity. And oftentimes, smaller fires, less frequent fire is more likely to be large fires high severity, or high intensity fire. So there's those interactions always going on within those different measures, or metrics of fire.

Megan Kay: 14:45

Yeah, is that does it did that, Matt, did you guys want to add anything or like maybe, maybe also, some context is like how we use fire regimes as well.

Matt Brooks: 14:55

Since you threw a quote out there, Stan, I'll throw another one. And it has to do with, you know, firing humans can also be characterized as fire over space and time. And one of the things about the Mojave in particular is that there's a wide range of variations in fire over space and time. And Robert Humphrey in 74, he had a seminal publication on fire in the deserts of North America. And his quote was, because of the inescapably close correlations between prevalence of fire and the amount of fuel deserts are characteristically less affected by fire than most ecosystems. However, even though fire frequency and severity may be relatively low in any rating scale, their effects on the ecosystem may be extreme. And the point being is is that in a place like at the more arid end of the spectrum with a lower fuel and the fuel end of the spectrum in Southern Nevada, especially at the lower elevations, fire can be very infrequent. But when it does happen, it can be a really significant ecological and management event. And because the fire regimes vary, so dramatically, even over the space of a couple miles as you go up in elevation, or down in elevation. And so I would just add that, you know, fire regimes are sort of characteristics of, they can be characterized as a very local scales, they can be a watershed, they can be a north facing slope on a watershed that has a different fire regime than they the the desert that's down below it that the watershed spreads down to, because fire might occur over time relatively frequently at those upper elevations. But as soon as it hits to the bottom of the watershed, there's not enough fuel to carry it down into the flats and into the basins. And so I think that's one thing, just to add is that it can vary, regimes can vary really locally, over time, but then also, they can vary over over centuries, decades and centuries, with changing climates. So you might have vegetations, and move up sloping down slope, it's really been dramatic in the Mojave in that regard, over time, because you have such a wide range of cover from less than 5%, shrub cover to to, you know, 40% 45% at the top of mountains in the same geographical area. And so that would be the main thing that I would add to that is that it can vary tremendously over short landscape features. But which makes it really difficult to manage sometimes in that context.

Ali Urza: 17:33

I think that one thing when I was thinking about the questions that you sent us, one thing that I kept thinking about was how our ability to understand historic fire regime is really complicated. And it's very challenged in places like Nevada or arid ecosystems, especially well, for a couple of factors. So one, like the, the less frequent fires are on the landscape, the fewer records, we have them over long periods of time. And when we think about fire regime, like Stan said, having a single fire doesn't give us a lot of information about a fire regime, we really need multiple fires to understand kind of the spatial and temporal pattern. And when we have pretty relatively few fires on the landscape, we just have kind of a more limited ability to understand the longer term patterns and because the occurrence of fires are, is really driven by temporal variability and weather conditions, like Matt said, or spatial variation over small scales, the fewer records we have, the harder it is for us to understand kind of what that pattern looks like. And then the other side of it is the form that the that fire records take is a lot more challenging in ecosystems that tend to experience higher severity fires with that our stand replacing or ecosystem or vegetation replacing. So the ecosystem types that we have really good records of fire for are like for example, ponderosa pine ecosystems where we tend to have high frequency low severity fires that leave a record of fire in the form of fire scars that we can date at an annual resolution and reconstruct over various spatial scales. And in desert ecosystems. We don't have those high precision records of fire. So our understanding of historic fire regimes is a lot more limited. And there's a lot of debate over what historic fire regimes looked like in desert ecosystems, really driven by that kind of lower fidelity of fire records.

Megan Kay: 19:48

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Stanley Kitchen: 21:58

First, I'd like to start with when we're talking about fire in Nevada, or fire in the Great Basin. And I'll maybe without thinking too much, use those interchangeably. The Great Basin and Nevada are not exactly the same geography but but close enough for our purposes, I hope that we have over 100 mountain ranges and each of those are somewhat unique from from each other there. And then they're separated by these dry valleys and so my emphasis has been working in the mountain systems and and Matt and Ali spent a lot of time in the valleys and so I'm part of my purpose will be to make sure that the mountains are well represented and what's going on and in those 100 or so mountain ranges 100 plus mountain ranges. There's a lot we don't know yet but there but we have learned a lot about the ecosystems and the place of fire and those ecosystems. And one of the ways we do that is through dendrochronology which is a study of tree rings. And the very simple explanation is trees produce a new growth ring on the just under the bark on an annual basis. So as the tree gets older, it's put it's producing a new ring and those rings can capture information about the environment as they are produced. And so they produce a sort of a history of the local environment including things such as fire and and b b oftentimes fire won't insure that the tree without killing the tree and that injury is captured in and ponderosa pine is the one of the better trees for recording not just a single fire but multiple fires and these are fires that tend to burn along the ground and the end and maybe into the brush or a small trees but are not the big crowny fires that usually make the news where all trees are killed and you're left with kind of a moonscape. these are these are low severity, low intensity fires, and or ground fire surface fires. So often a tree when it once it's been injured, once it can be injured multiple times bark will fall off that and it will leave an injury area that's easily recognizable on the trunk of a tree and kind of a triangular pattern. And as we look in that that injured area without bark, there will be charged from fires and and evidence within within those growth rings a pattern of growth rings of of those injuries that by cutting a cross section through that we can examine the growth rings and see right to the year when those fires occurred in the past and and so it's not uncommon in some places where fire is frequent on the landscape. We might see evidence of anywhere from from a few to 10 or 20 fires recorded in a particular tree. And then if we gather information from multiple trees, say in a watershed or from on a hill slope or across an elevational gradient, then we can start putting together ideas about the pattern of fire both through time and space on that landscape. And that's been a lot of what I've done. In some of the mountains of Nevada there's there's been others to some other researchers that have worked in the sheep mountains and and the clover mountains and Irish mountain in Nevada. I've worked in the snake range and the Shoal Creek range. Those are areas where ponderosa pine is found. And so it's easier to make this kind of a study though, though I have, I have observed fire scars, and not just ponderosa pine, but limber pine, bristlecone pine, white for Douglas fir.engelmann spruce, even quaking Aspen, at times can form distinguishable fire scars, so it's, it's, it's just a little harder, when you don't have that, that species like ponderosa pine helping you out. So So then we we, we can make these temporary these, these histories of that are connected to a particular tree. And again, with multiple trees on the landscape, we can put together both patterns of spatial patterns, as well as temporal patterns of, of how fire is on the landscape. And sometimes when the fires are high severity and they kill all the plants, then then you can sample those trees and know the year that they died in also as a as a way of getting at those records. Or even when a forest has opened and opened up. Because of that kind of a high severity fire, you get new trees established afterwards. The dates on when those trees first started growing can also help tell you about the last event of a fire.

Christina Restaino: 27:03

I love looking at tree rings my entire all of my dissertation work was a giant tree ring study. So I I love looking at tree scars.

Megan Kay: 27:13

So I'm going to circle back and then after because I want to ask Matt and Ali something but I'm going to circle back and ask about the changes in fire that you've noticed, historically. But first, I want to go to Matt and kind of ask. So we just heard about how you study the history of fire with Ponderosa pines and in forest where their stands of trees. How do you study the history of fire in the Mojave Desert?

Matt Brooks: 27:39

Yeah, so I think a good segue for what Stan described was, was an example from the ecotone between the Mojave and the great basin. And that includes individual sort of sentimental trees that that dendrochronology has been done on. So I'm talking about the sorts of trees Stan's talking about where you get hundreds of them across the landscape. And you can figure out spatial patterns over space and time. Individual tree much more difficult, but it provides a tremendous amount of information about the general frequency of fire in an area. So I'm talking about these individual pines that are in an area that's now currently sagebrush, and pinyon, and Juniper. And there's an example from you mentioned, the Irish mountains and his mad Irish publication, where for hundreds of years up until about the mid 1800s, when the ranchers came in, there were fires that occurred sometimes sometimes less than, you know, a decade between fires, but pretty, you know, relative regular burning in this region. And then as soon as the ranchers came in, the burning almost ceased that record in the tree. And the inference is, is that there was a tremendous amount of burning by Native Americans probably for things like perennial grass production, pinyon pinion production seed production. So there was I think that in the Mojave, there is some inferences. Well, that's actual evidence. But there's also references from traditional knowledge from native tribes about especially in riparian areas for managing mesquite Mesquite was a very valuable crop. And you get higher production if you were to if you wrote regularly, regularly clear around them.

Megan Kay: 29:30

Could you tell us why mesquite was such a valuable crop just out of curiosity,

Matt Brooks: 29:35

it's a it's a high protein, food for making meal. kind of like the opinion seeds, but it's in the it's in the context of riparian systems. Also, in a landscape like the Mojave where water is at a premium and really water dictates whether human habitation is possible even today in regular burning around Spring sites would increase spring flow we know that today it's it clearly happened in the past there's evidence that that was done in the past also basketry materials things like milkweed

Megan Kay: 30:12

so is that because you're clearing away anything like dead vegetation and build up like is that why well

Matt Brooks: 30:17

basically it's evapo transpiration, reducing vegetation amount, you increase the amount of flow to the surface for a period of time. And so we infer a lot from on past fire frequencies and and and from traditional knowledge that's been passed down also like I gave an example of embedded trees. But other evidence is there's there's a very rare occurrence I know of a couple of publications that are actually publications looking at seismic events. And basically it's it's, it's, you have the strata that are laid down in a deposit over time, every once a while you get a carbon lens from a fire and the the use the the earthquake, scientists basically use those carbon lenses to carbon date them. And where there's a displacement of a carbon lands and a certain level, they can determine that there was a seismic event. So in the western Mojave, there's there's a couple of examples of publications done by seismologists to look at earthquake histories that can give you an idea of layers of carbon, charcoal carbon, basically, we're talking about an idea in an LED in a watershed anyway, frequency of fire. But most of the evidence really has been kind of working back the other direction is, is been on documenting vegetation changes over time, and inferring the regimes that go along with them based on current relationships, so packnet packrat mittens, for example, are we are pack rats or big rats that that have big piles of things and rocks with vegetation material. And basically they bring vegetation material in there that represents the area around their their little den, and base with urine and feces deposit over time, it crystallizes and almost magnifies it, and creates records over time that build up are stacked on top of each other. And these usually rock crevices, that can document changes in vegetation in the surrounding landscape based on the composition, as well as the relative proportions of the vegetation. And so those can document back to almost 50,000 years. I don't do that work myself, but

Megan Kay: 32:41

I there are those in are those present in Nevada? And like Southern Nevada?,

Matt Brooks: 32:45

Yes, yes they are. And they actually are better preserved as I understand it in drier, warmer, drier climates. And so it's really a valuable thing in the high deserts to determine vegetation composition over time. So for example, there is evidence that different mittens up a watershed show that vegetation types like pinyon and Juniper ecotones with like black brush have moved up and down 1000s of feet in elevation, during the Holocene even which is last 10,000 years since the last ice age. So that's actually a really valuable thing that allows us to look at changes in vegetation, and then infer the fire regime that would go along with it, especially things related to perennial grasses. And And lastly, Pleistocene during the Pleistocene ice ice ages waning and waxing and waning. The levels of the the, the, the lakes, the Pleistocene lakes in the Mojave, as they go up, it's a wetter period as they go down. It's a drier period, and so you infer what's happening in the greater landscape around them in terms of vegetation, formations, from grasslands, to woodlands, mostly, not so much for us for us up on the mountaintops. But oak woodlands even were pretty prevalent in the Mojave during different times during the Pleistocene. And you know, these these go back the Pleistocene goes back about two and a half million years. The Mojave Desert is considered to have been a desert regions anywhere from the last two to 5 million years. So there's different scales of time that you can go back and different types of evidence to infer it's not direct evidence of fire really likes what Stan described with a with a charred remains on the rings in the trees. But it gives us a general idea about the prevalence and and type of fire that was occurring and in general the fire regimes

Megan Kay: 34:40

thanks for painting that picture. Yeah, cuz it's, it's really interesting for me, for me and I think it will be for our listeners to kind of understand how you guys are piecing this stuff together. And then at alley, I want to ask you the same question based on like the valleys in the Great Basin maybe where there's big where they're sagebrush, and not Trees.

Ali Urza: 35:01

So a lot of the overall topics that Matt and Stan just talked about also apply to sagebrush and pinyon Juniper systems, which are kind of the two major ecosystem types that I work in. But so like, for example, in pinyon Juniper ecosystems, we do have some studies that have direct evidence of fire pinyon and Juniper. Species typically don't survive fire well. But occasionally pinyon pine will form scars if it's on the edge of a fire perimeter. And so there have been studies that have crossed dated fire scars from pinyon pine to provide kind of direct evidence of fire history within particular locations. And then, you know, we additionally can use stand ages, so the ages of trees within a woodland stand to infer something about the disturbance history pinyon and Juniper species typically don't establish right after a fire, like more montane species might, they might take decades to come in after a fire. So they're not exact dates in the same way that they might be in other fight more fire adapted ecosystems. But that is helpful evidence to help us understand kind of the general trends over time. But what Matt said about inferring disturbance history and fire history based on vegetation patterns, I think is really key in some of these more arid ecosystems. And one of the things going back to a point that Stan made earlier to one of the lines of evidence that we can use when thinking about general fire patterns or disturbance patterns through time is using our understanding of the traits of the species involved in their life history strategies. And we know for example, based on kind of more contemporary observations, as I mentioned, pinyon and Juniper, typically don't survive fire, and they often take many decades to reestablish following fire. So for example, the presence of an older aged, persistent pinyon Juniper woodland stand tells us something about the prevalence of fire in its past. And so we know that, you know, if there is a persistent pinyon Juniper woodland stand with, you know, many trees that are several 100 years old, we can infer that there hasn't been fire on that landscape within several 100 years, or at least large, large enough fires to kind of alter that vegetation pattern over the broader landscape. Similarly, with sagebrush, sagebrush, the dominant sagebrush species in Nevada, big sagebrush isn't particularly adapted to fire, it doesn't really sprout after fire, it seeds don't disperse very far. So especially in the drier landscapes, sagebrush takes at least a couple of decades to recover after fire. And so we can use that information or that understanding of the species life history strategies to understand that, you know, very frequent fire on the order of, you know, a couple of years of rotation was probably unlikely over long time periods in sagebrush ecosystems. Yeah, Stam had his hand up, I just do want to make sure that I say that all of these patterns are extremely variable through space. And one of the interesting things about Nevada and the Great Basin is just how variable fuel composition, whether soil depth and productivity in general is across even very short spaces. And so fire history might have been very different in a valley bottom versus just upslope versus higher upslope on on rockier soils that have that are less productive and have lower grass and forb cover that can kind of carry more frequent fires,

Stanley Kitchen: 39:06

like what Ali had to share in terms of sagebrush, we've done quite a bit of work and others before me at looking at, well, if, if, in terms of the frequency or the, the length, the period of time necessary for there to, to, if you're going to have a sagebrush system, what's the minimum amount of fire or the minimum period of time without fire that that conceal sustain is a sagebrush system and, and certainly, we know that mountain sagebrush so there are different subspecies of this big sagebrush that Ali alluded to and the in montane systems that the the subspecies that lives in mountains, tends to be able to come back much more quickly than it can in the valleys. And so we say, Well, if If If sagebrush can come back in two to three decades, there's not a lot of there's there's still some disagreement about how long it takes. And it can differ on the same spot from one fire to the next through time. But But let's say on average somewhere between two and 20 and 40 years, oftentimes sagebrush stand in the mountains comes back and it's, it's pretty reached its near its climax or that level of, of well established sagebrush community, then if you have a fire regime in which you have fire occurring every 10 years, you know, it wasn't a sagebrush community on that, on that particular location. If it was, if you have some record that indicates that fire may have occurred 60, 70, 80 year intervals, and then that may indicate that it was very compatible with a mountain sagebrush community. If it's on, if it's in an area that's subject to encroachment by trees of pinyon Juniper, but sometimes it's first, sometimes it's ponderosa pine, and you're going 200 years or 300 years without fire, then that same landscape may convert from a shrub land now to a forest or woodland. So that interaction between the vegetation is going to dominate on the site. And the frequency of fire on that site can be very dynamic and change through time subject to that that frequency of, of when that disturbance events takes place, and how often or where the sources of, of new propagules, seed or whatever to repopulate the location after a fire event.

Megan Kay: 41:53

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Christina Restaino: 42:24

It's important to point out and I would love to hear your your perspective, either Ali or or Stan on this. There's this there's a lot of different species and types of sagebrush in Nevada. And so there are the dynamics of what other plants exist within the sagebrush community, modify how fire behaves on the landscape. And so Allie, I don't know if you want to say a bit about that.

Ali Urza: 42:55

I have to think about it for a second. So there are there are kind of multiple parts of that question. So So yes, there are different types of sagebrush that do seem to there are different subspecies that have been identified that do seem to have different traits and have different abilities to respond to fire. But probably more importantly, is the differences in climate that those subspecies occupy the differences in the plant community that they coexist with. And so certainly when thinking about kind of drivers of patterns of fire, the abundance of fine fuels, so in historically these would have been primarily perennial grasses but but in kind of more contemporary terms, and this is also sort of moving into the conversation about recent changes in fire regimes. We now have a large abundance of non native annual grasses, which provide a more continuous fuel surface at the lower elevations where they tend to dominate the most, and that can increase the frequency of fire, it increases the length of the fire season. Those annual grasses also such as cheatgrass tend to be very adapted to fire so fire can actually serve as like a inducing event that can facilitate the the initial invasion of those grasses or increase their dominance on the landscape, which then gets into the, what's termed the annual grassfire cycle. A lot of Matt's work is focused on this so I definitely don't want to talk too much about about that side of things. But certainly, there's so much variation in the role that fire plays across the landscapes in Nevada and especially in kind of the Great Basin portion of Nevada that I'm most familiar with that even just moving you know, uphill from the valley bottom to a couple 100 meters higher in elevation. You have completely different landscapes that that exists under very different climate regimes with very different fuel compositions and the role of fire and the interaction between vegetation and fire is just so different between them that it's very hard to make kind of blanket statements about fire regime and sagebrush ecosystems, for example.

Matt Brooks: 45:18

Yeah, I do I have permission to complicate the conversation.

Megan Kay: 45:22

Yes. But I also wanted to put make sure you guys are thinking about because I do want to, because it's coming with both Christina, Stan and Ali, I do want to think starts also thinking about how fire regimes have changed. Like you're talking about cheatgrass invasive species, and then how the relationship between fire and vegetation and humans has changed these ecosystems so I didn't I don't want to derail you. But I also want to put that in your brain to start thinking so

Matt Brooks: 45:49

Ao I can complicated in segue, how about that?

Megan Kay: 45:51

Sounds good.

Matt Brooks: 45:53

So the My only booked for the complication is that the discussion here in the great basin was sagebrush has been about how different species vary in general, in terms of their resilience to fire, so like sort of like their evolutionary history with fire and their ability to, to persist in a landscape that also has fire. So there can be variations also within those species, local eco types. One of the challenges we have in the Mojave is that we have these things called sky islands, the top of the mountains are little remnant Great Basin enclaves. So they're little great basin landscapes on the top of a mountain, and the bottom and the valleys. It's creosote, and saltbush, and Mojave, and the islands in the mountains are climatically and vegetation wise, these little species compositions that make some Great Basin. And so understanding how those species how those how, how great how big sagebrush in the Mojave, how is it that has the same resilience as a big sagebrush that's in a flat in the Great Basin? And so we rely a lot on information from the Great Basin to infer what's going on the high in the Mojave. But really, that's a big question that sort of remains. But the conversation is kind of going more towards sort of fire ecology. And so I'll steer steer you back to what you were talking about wanting us to go. And that is how things have changed. So I had mentioned about how the fire frequency and amount Irish area, the inference is that the history of indigenous burning was was changed when the ranchers came. One of the other things that we found lower elevations there's actual you start getting into evidence of fire through historical documents. So early part of the 19 hundred's especially into the well into the 20s 30s and 40s. There is agency documents in the Mojave that exists, a lot of it from Lincoln County, Nevada, which is ecotone, between the great basin and the Mojave where there was a lot of ranching going on. At that wet that give us an idea about how that had changed things. So the land use of livestock grazing. So in around the 30s, late 30s and 40s, there was evidence that there was actually an estimate that about 20% of the black brush in Southern Nevada, was burned by ranchers to try to promote more forage in particular perennial grasses. This is a period of time at the end of a multi decadal period of higher rainfall. And then in the late 30s, early 40s, there were some really high rainfall years. So the opposite My guess is, is that the observation by the ranchers was, hey, there's a bunch of Indian rice grass grama grass, that burning that's lives in between these black brush. If we could burn the black brush to premium grass would come up, we'd have more forage for livestock. And so they ended up burning a lot. And there was a lot of records from that, that were that are still in existence, I actually have gotten from some of the sub county field office in Southern Nevada being one of them. And there were photographs they took. So there's some actually really great evidence from records, photographs, journals, and reports. That indicates that there was a fair amount of burning going on at that time. From the standpoint of black brush, we now consider black bread, something that doesn't survive well with fire. And so it's interesting to kind of think about, there's a lot of black brush in Southern Nevada today, if there was all that burning going on was there a lot more if it hasn't recovered. But some of the old photographs we've used we revisited these photos from the 30s and 40s and found black brush and pasted places that show completely stan replacing black brush, slicked off just dirt a year after the fires. And so there's this is another sort of evidence of more how the settlement had changed started to change fire regime and some of the evidence we use photographic evidence to figure out maybe how resilient things like even black brush might be. And you go into think about more more, thinking more. You No more deeply. And black brush at the edges of its ranges probably is more resilient because it's an it's in an interface with other vegetation types for fires occurred more frequently, I've found black brush re sprouting, and the interface with the Sierra Nevada Mountains in the far western Mojave. And it's on the edge again of a different fire regime. And so when you find vegetation types, whether it's great bass and sagebrush, or whether it's big sagebrush or whether it's, it's black brush or whatever, that's far ranging, at its interface with other vegetation types that burn more frequently, there's a strong likelihood that that that species has a different resilience than it does in other areas, because it's experienced a different historical fire regime than maybe it occurred in the center of its range. And so that's, that's sort of a description of another way we look at fire regimes. It's also something about the changes of fire. The interesting thing about so I'll just finish this little data dump with those five, those photos, some of those photos from 40s, show landscapes covered in red broman cheatgrass in the 40s, after they burn black brush, and that's an elevation zone today where we find the brown species, both those species to be most prevalent, and the biggest fire contributor is really in black brush and the upper elevation, the creosote bush. So it's kind of fascinating that back there, this it this there was the thing that we think more of is something that's evolved since the 70s, at least in the Mojave with red Rome. Photo evidence suggests that, that it was very prevalent postfire back during that period of time, and it only is it was recorded red brome anyways, from North American late 1800s. So relatively quickly, it got to a point where it can cover around landscape in Southern Nevada after black brush burn as early as the 40s

Megan Kay: 51:59

was, I mean, did people consider it? I mean, it wasn't that much of a hazard I'm sure, like people wanted those grasses for forage for animals and things like that.

Matt Brooks: 52:09

Well, it's more of the perennial grasses that that that have higher nutritional content poaching content, also the annual grasses and they dry out their high Silikal. They're not as palatable but definitely palatable but but what's interesting is that the series of reports, it shows how, and these were these were actually from a predecessor of Intermountain Research Station, I forget what it was, it's called there's something Las Vegas grazing district or something. Stan, you probably know more about this history than I do. But there was like about Ralph Holmgren was one of them. One of the guys that was on this, and I think he's from the Salt Lake area, I remember correctly. But at any rate, there was about five or six authors on these on these reports. And one of them put an addendum to a report stating that, that yeah, this did go good. You know, I agree with everybody else that burning did reduce shrub layer is quite a bit and, and a cover, but I'm concerned about this red brome being something that might promote really frequent fires. Nobody, nobody told him in any publications or education that that was this thing called this grass fires cycle with annual grasses for the Mediterranean region. And but it was really interesting that that he saw his perception of how much fuel there was fine fuel a couple years after fire on the landscape was was significant enough for him to put in writing. And what year was, is the probably the late 40s report was about these field visits. So yeah, there's some just by chance that was, you know, records that have not been thrown out over the years from agency offices that provide a really, I think, fascinating insight into what was going on in the management side of things during that period of time. And it's not this is not typical Mojave. This is more of an ecotone region between the Mojave in the Great Basin, but it is in Southern Nevada.

Christina Restaino: 54:08

So so I'll just add, I don't believe that anybody was excited to have the the broam cattle don't care for it. sheep are the ones that in springtime only will consume the TCE graphs and maybe the Brom I don't know as much about that, but I know that but I'm not sure that sheep are introduced until later, so I'm not sure that that it was ever considered an advantageous thing to have on the landscape.

Stanley Kitchen: 54:40

Alright, then, let me add a little bit inside I have available a you know, in 1992, we did a symposium basically it was an annual grass symposium in the gray basin. And I thought that was we were like cutting edge or something until I ran across proceedings of a symposium that was in In the late 50s, and it was called the cheatgrass symposium. And what have we learned so far about cheatgrass is what it was about. And, of course, it was a very different perspective than you think think late 50s, early 60s, right, I can't remember the exact year but but many of the papers that were presented in that symposium talked about cheatgrass in a favorable way that it's on that they talked about the biomass available production, compared to some systems, when cheatgrass is not present. She came into some portions of the Great Basin and certainly in the Utah portion in eastern Nevada, as early as the 1870s. And so that they've been around for a while cattle, certainly a little bit longer than than sheep, but both of them quite for quite a long period of time. And they saw cheatgrass as a valuable forage that was not always dependable as a good way to put it, I think and, and somewhat short lived, but still still as portrayed. Now this is not all of the presentations, but but many of the presentations portrayed it is, is something perhaps more favorable than we see it today. And the potential effects of fire either were not considered very much or they were considered in a more favorable light since fire could get rid of, sagebrush. And sagebrush was considered part of the enemy that we needed to get rid of. So we could grow more grass. And so that opened my eyes up a little bit in terms of how long people have been looking at that cheat grass and trying to decide what to do with it. And I'm not sure yet in my own mind, how much progress we've made in 70 years,

Matt Brooks: 56:50

I'll just, I'll just add that from a perspective of what drives fire in the Mojave, the thing that Trumps any of what we've discussed so far is climate for the Mojave, its fuel limited. So for example, what I just described about the burning by being Southern Nevada during the 40s 30s and 40s, that was at a period the end of a period of a multi year multi decadal period of drought from about 1900 to not drought, higher rainfall 1900 to about 40 from 1940 to 75. It was a period of very low rainfall in the Mojave, often referred to as the mid century drought. And I I don't think I'm able to find a single record of fire from the Mojave during that time and then started in 76 through especially 2006 period of higher rainfall some El Ni o years and and it was almost li e the the at that period of tim, the fire the fire managers w re just starting to say hey, t ere's fire has never happened b fore. And it's it's because f re oftentimes don't have the h storical perspective. They j st have how long they've been i the field office and that p rspective and, and so fire i crease during that period of t me really has been was can c incident with increased i creased rainfall. I terestingly, when you talk a out bromus, there's a series o the Nevada Test Site with J nice Bailey from UCLA was p oduced a lot of the great i formation on on an annual g oss annual plants and plant c mmunities in Southern Nevada, s arting in the 60s, and the N vada Test Site was a place w ere she was contracted to do s rveys. And there's a p blication that one of the p ople that work with are R chard hunter road. And he b sically showed in the records o the Janice beatley Records s arting in the 60s, up through I think it was 79, this e ponential increase in red bone d nsity. And his publication was a d this is red Roman baiting t e test site. Starting in the 6 s. Why just told you that t ere was public, there's p ctures in Southern Nevada of u covering a post fire landscape f om the 40s. And his p rspective was coming out of t e mid century drought, right. A d so red brome was at an era a a level where you could i entify swathes of in in black a d white photographs. And you k ow, somebody was enough there f r somebody to make a note of i in a report during the 40s. A d yet, the perception was that i was just invading and about S uthern Nevada in the 60s. More t an likely it was knocked back d ring that mid century drought. S so some interesting sort of h storical perspectives about l ke Sam was talking about the p rspective of cheatgrass then a d now we have to kind of think a out the perspective of, in t is case, red brome on the l ndscape, but also the p rspective of fire on the l ndscape based on historical c ntext, and oftentimes I try to I try to describe like the q estion being, you know, where a d when is fire of use or could b considered to have positive r source benefits in the Mojave A d I always have to say it's in t e context of the historical c ntext. And, and then, of c urse, what your resource b nefit definitions are. But r ally, I think the underlying t ing about this, the whole t eme of this podcast being h story of fire, is how does it h lp us manage today? How does i make help us make decisions t day, given the history of f re? And what we know about it? H w does it help us make m nagement decision today, and a l these different things we've b en talking about all c ntribute to that.

Stanley Kitchen: 1:00:32

Fire is best viewed as, as a tool. And it's just one of the tools we have in the toolbox. There there, there are other tools, including doing nothing, but that there's consequences the use of all of the tools. So we need to use those tools as wisely as we can, and keep this full toolbox as we as possible. So we have lots of options that we can deal with, learn from the use of those tools, and use them as wisely as possible in a changing and and sometimes unpredictable future that we have in front of us. We've occurred a few times today, the idea of fires both can be good or bad. And I would go back to a quote, the way I started, this was from Bob keen, he said, fire is neither good or bad fires an important cological process that can roduce variable effects, the alue of these effects must be nterpreted in the context of uman desires and needs. So here's this interaction of ires just a process, it's omething that happens, it will lways happen, as long as here's fuels available, and here's any ignition source and enough oxygen in the atmosp ere. And we can look at the la dscape and say, Is it better that we use fire in the timing that we would maybe want to app y it on this particular landsc pe or some other distur ance process that would get it get an ecological outcome that's preferable? Or are we just g ing to let fire happen on its te ms, sometimes as under the mo t severe fire climate, think alifornia the last few year, and, and we just, we just get ut of the way and left and then try and clean up the mess afte wards. That's where fire has place. Because we can deci e that that's where pres ribed fire has a place that we c n decide when and where and how t's applied. If we just back away and don't use it at all, and wait for natural fire to o cur, sometimes it's in the wron time, the wrong place, the wron circumstances. And the role results can be much worse.

Ali Urza: 1:02:41

Yeah, what I was thinking about ending on was kind of parallels a little bit of what Stan was talking about. But I just think it's in the management context, it's really important to emphasize that fire, like any management tool has trade offs. And those trade offs very, very quickly through space, depending on the ecosystem type that that we're looking at. And the trade offs are really going to change as we move into the future in different climate conditions. With different species compositions, we have a lot of non native species that are becoming more prevalent in the Great Basin. And so I just think it's really important, like I completely Second, the sentiment that they're thinking about fire as good or bad really oversimplifies the issue. It really is an issue, it's a matter of trade offs. Among competing values really are competing conditions on the landscape. And sometimes there isn't a clear, you know, correct condition that we don't have 100% clear vision of what historic conditions were, we know, the historic conditions were quite variable, we also know that, you know, given the changes that have occurred, it's unlikely that we'll ever be able to fully mimic historic conditions, whatever they might have been. And so I think it's just really important to have transparent and open conversations about the trade offs involved with all management tools. And we still have a lot to learn about what exactly those trade offs are. And sometimes we see huge surprises, you know, related to ecological or, you know, economic effects on the landscape after applying certain management treatments, or management approaches, and so anyway, I think that's just my, my main takeaway, kind of integrating these ecological management, content concepts is just that it's really important that that conversation be really transparent and honest about what those trade offs are. And the fact that our societal values change through time as well. And so what we're managing for and what we see is valuable or good on the landscape changes very rapidly and so yeah, it's just important to keep that in

Christina Restaino: 1:04:57

It often changes, more rapidly then the mind. planning processes and laws allow us to it changes at a quicker pace than those do.

Ali Urza: 1:05:09

Yeah, absolutely. I mean, I worked before I went into research I worked as an ecologist for the BLM. And I would always just laugh it, you know, being out in the field and see these swats from just a few decades ago of aerial herbicide eating of huge sagebrush stands across huge landscapes. And when I was working there, probably 50% of our annual budget went into sagebrush restoration, replanting, and all of that, and it's just, it's, it's a little bit frustrating and it kind of how quickly the pendulum swings back and forth. But I think that, you know, like I said, I think that missing from a lot of those conversations is just really an open discussion of what the trade offs are and being really explicit about what values we're managing for and why. So that when our when our values do change, we you know, have a good understanding of how our management can change accordingly.

Megan Kay: 1:06:15

Thank you for listening to the living with fire podcast, you can find more stories about wildfire and other resources at living with fire.com. The Living of fire program is funded by the University of Nevada, Reno, extension, Nevada Division of Forestry, Bureau of Land Management and the United States Forest Service.