Coexisting with Fire in Rangelands

Victoria M. Donovan, postdoctoral research associate, Department of Agronomy and Horticulture, University of Nebraska–Lincoln Author

02/25/2021 Added

21 Plays

Description

Large wildfires have surged in recent years in the Great Plains. While fire is a fundamental rangeland ecosystem process, it can also pose a risk to human life and infrastructure. How can we coexist with fire? Donovan will present recent research on changing wildfire patterns and suggest directions for future management.

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[00:00:00.820]The following presentation is part
[00:00:02.720]of the Agronomy and Horticulture Seminar Series
[00:00:05.860]at the University of Nebraska-Lincoln.
[00:00:08.510]Thanks everybody for coming.
[00:00:10.100]My name's Caleb Roberts.
[00:00:11.890]I have the pleasure today
[00:00:13.440]of introducing Victoria, or Tori, Donovan.
[00:00:17.330]She is a native of Canada.
[00:00:22.010]She got her bachelor's at Queens University in Ontario,
[00:00:26.230]and, Laurentian University in Sudbury, Ontario,
[00:00:29.070]and then she moved down here to be in Nebraska,
[00:00:33.560]and got her PhD in the Agronomy Department, UNL.
[00:00:38.720]She studies landscape ecology,
[00:00:42.500]and has a lot of her research, obviously, with fire.
[00:00:46.100]One of her papers, "Surging Wildfire in the Great Plains",
[00:00:51.010]published in 2017,
[00:00:52.130]she had some interviews with the Washington Post,
[00:00:55.020]got some national news on that, some really awesome stuff,
[00:00:59.100]been cited many times.
[00:01:01.060]More recently, I mean,
[00:01:02.100]she's already knocked out three papers for 2021,
[00:01:04.567]and we're only two months in, so pretty great work
[00:01:07.990]that she's published in the "Ecology and Society",
[00:01:09.747]"Biological Conservation", "EARTH Futures",
[00:01:14.339]and multiple papers in rangeland, ecology, and management.
[00:01:17.550]So today she's gonna be talking to us
[00:01:19.260]about coexisting with fire in rangelands, so.
[00:01:22.210]Awesome, thanks so much, Caleb!
[00:01:25.410]So as what's said, my name's Victoria Donovan.
[00:01:28.160]I'm a postdoctoral research associate here
[00:01:31.030]in the Department of Agronomy and Horticulture.
[00:01:33.510]I'm really excited to be invited to talk today.
[00:01:36.910]And today I'm gonna be talking to you
[00:01:38.140]about coexisting with fire in rangelands.
[00:01:41.680]So I'm sure many of you are used to seeing images like this
[00:01:44.870]in the news at this point.
[00:01:46.460]This is a picture of some California wildfires
[00:01:48.750]from back in October 2020.
[00:01:51.765]And we're seeing news stories like this increasingly,
[00:01:54.840]you know, a lot of increasing wildfire activity,
[00:01:57.900]particularly documented out West,
[00:02:00.525]a lot of damage to property,
[00:02:03.380]and this is causing wildfire to be a big issue
[00:02:06.359]and a big discussion topic here in the US.
[00:02:11.100]Now we know that large wildfire risk out West
[00:02:14.600]has been quite high, or has been deemed quite high.
[00:02:18.520]You can see this map that I've altered
[00:02:20.230]from the National Cohesive
[00:02:21.520]Wildland Fire Management Strategy.
[00:02:23.804]All the dark red areas are areas that they've designated
[00:02:27.610]as high risk for large, long duration wildfire.
[00:02:31.440]So you can see the West has a lot of high risk areas,
[00:02:33.900]whereas if you look at the Great Plains,
[00:02:35.520]which I've outlined in black,
[00:02:37.220]you can see that this region has largely been designated
[00:02:40.080]as an area that's low risk for fire,
[00:02:43.120]and this has been pretty consistent over the last century.
[00:02:47.190]But as Caleb mentioned, with my publication back in 2017,
[00:02:51.870]we actually identified that this is changing.
[00:02:54.740]And so we actually found across the Great Plains,
[00:02:58.160]we're seeing surges in wildfire activity.
[00:03:00.610]We had a 400% increase in the total hectares burned
[00:03:04.420]by large wildfires, and a 350% increase in wildfire number
[00:03:09.210]between 1985 and 2014.
[00:03:14.160]Now, we're seeing that there is a lot of spatial patterning
[00:03:17.470]associated with these increases.
[00:03:19.360]So in these maps of the Great Plains I've got here,
[00:03:22.580]I've isolated different eco regions in the Great Plains,
[00:03:25.490]which are basically a way
[00:03:26.680]that we can subset the landscape to look at areas
[00:03:29.890]with similar biophysical and geophysical properties.
[00:03:33.900]I've color coded each one of these ecoregions
[00:03:36.580]based on the rates of increase in wildfire number
[00:03:39.770]and total hectares burned,
[00:03:41.730]where the darker red areas are areas
[00:03:43.960]where we saw greater increase in those two variables.
[00:03:48.340]So you can see in terms of wildfire number,
[00:03:50.820]we saw some of our greatest increases occurring
[00:03:53.300]in the western and southern regions of the Great Plains,
[00:03:56.446]whereas for total hectares burned,
[00:03:58.350]we're seeing a lot of our increases
[00:03:59.760]occurring along this western border of the Great Plains.
[00:04:04.850]Now, of course, when we find this results,
[00:04:06.670]one of the first questions that we ask is why.
[00:04:09.270]Why are we seeing this change in wildfire activity
[00:04:12.240]when we've had almost no large wildfires
[00:04:14.530]occurring in the Great Plains of the last century?
[00:04:17.190]And we can really investigate fire by breaking it down
[00:04:20.580]into these three different components
[00:04:22.360]that we know fire needs to exist.
[00:04:24.910]So we need an ignition for fire to start.
[00:04:28.330]We also need weather and climate that is conducive to fire,
[00:04:32.140]and of course we need fuels for fire to burn as well.
[00:04:35.770]And so we can break it down
[00:04:37.250]and look at each of these components
[00:04:38.700]to try to understand fire activity and changes.
[00:04:43.410]So we talk about ignitions to begin with.
[00:04:45.570]We know that human ignitions have been extremely important
[00:04:49.090]here in the Great Plains historically.
[00:04:51.720]Before Euro-American settlement,
[00:04:53.790]indigenous stewardship of the land utilized frequent fire
[00:04:58.000]to help to maintain the grassland systems
[00:05:00.140]that we come to know today.
[00:05:02.190]And you can see in this map here
[00:05:04.130]that I've altered from Guyette et al. 2012,
[00:05:07.870]outlined the Great Plains here in dark gray.
[00:05:11.190]And you can see that we had a mean fire return interval
[00:05:15.030]of about 2 to 12 years, so very frequent fire.
[00:05:18.870]This made the Great Plains
[00:05:20.020]one of the most frequently burned regions
[00:05:21.950]in the continental US, but also globally, the Great Plains
[00:05:25.560]is one of the most frequently burned biomes.
[00:05:29.670]Following Euro-American settlement, as I've said,
[00:05:32.250]we saw this complete shift in how firewood is utilized
[00:05:35.600]and viewed on the landscape,
[00:05:37.280]and so we went from this application of fire
[00:05:40.970]by indigenous peoples to a complete halt in,
[00:05:44.100]or an almost complete halt in fire management
[00:05:46.830]across the Great Plains.
[00:05:48.330]And instead we switched to active fire suppression.
[00:05:50.930]So if we saw fires ignited through lightning
[00:05:53.858]or other types of ignitions,
[00:05:55.670]we generally move to suppress those as fast as possible,
[00:05:58.430]trying to eradicate as much wildfire
[00:06:00.280]as possible off of the landscape.
[00:06:03.481]And so one place that a lot of researchers have been looking
[00:06:07.850]is a change in ignition sources
[00:06:11.430]to see if that could be driving
[00:06:13.070]some of the changing wildfire activity.
[00:06:15.360]This is particularly of importance out West.
[00:06:19.050]We see in California, particularly,
[00:06:21.790]human ignitions are playing a large role
[00:06:23.850]in some of the increasing fires that we're seeing there.
[00:06:26.620]And so this is a map
[00:06:27.950]that I've stolen from Balch et al. 2017,
[00:06:31.520]and basically each one of these points in this map
[00:06:35.540]represent the number of fires and the percentage of fires
[00:06:39.190]that are human ignitions.
[00:06:40.023]So as the point size increases,
[00:06:43.240]we have a greater number of fires,
[00:06:45.320]and then as our color shifts from blue to red,
[00:06:48.390]we have an increasing percentage of those fires
[00:06:51.540]as human ignitions over their study period.
[00:06:54.760]And so you can see our Great Plains,
[00:06:57.280]I outlined here in the center of the continental US,
[00:07:00.740]you can see that the majority of fires
[00:07:03.680]that are composed of human ignitions are really occurring
[00:07:06.690]along this Eastern portion of the Great Plains.
[00:07:09.667]And if you recall, most of our large wildfires
[00:07:13.830]where we're seeing the greatest increases,
[00:07:15.513]is along this western and southern portions
[00:07:18.640]of the Great Plains.
[00:07:19.473]So while we know that human ignitions
[00:07:21.300]are playing a role here in the Great Plains,
[00:07:23.100]it doesn't seem like that might be a major driving factor
[00:07:26.370]for some of the increases
[00:07:27.610]that we've documented most recently.
[00:07:31.730]Another thing that's really important
[00:07:33.030]for us to think about is weather and climate.
[00:07:35.120]We know that this is playing a huge role out West
[00:07:38.350]in terms of fires,
[00:07:39.240]and there's a lot of research documenting that.
[00:07:41.630]While we have a lot of information in the Great Plains
[00:07:44.080]at smaller scales, looking at the interactions
[00:07:46.460]between things like drought and fire,
[00:07:49.610]we have a lot less information and research
[00:07:52.130]looking at these large scale shifts in wildfire patterns
[00:07:55.580]and regime characteristics relative to drought.
[00:07:58.180]So I'm just gonna show you some preliminary analysis
[00:08:01.110]that I've conducted on this.
[00:08:03.410]You can see here in our map,
[00:08:05.660]this is a large portion, at least, of the Great Plains,
[00:08:08.474]where I've taken out wildfires from 2000 to 2012.
[00:08:13.250]And we've color-coded those based on the drought conditions
[00:08:16.410]under which they occurred.
[00:08:17.880]So if you have a perimeter here
[00:08:19.160]that's colored in dark green, for instance,
[00:08:21.630]that's a wildfire that burned under very moist conditions.
[00:08:25.230]Whereas if you have a perimeter that's orange or red,
[00:08:28.610]those are more severe or extreme drought conditions.
[00:08:31.580]So you can see, again, this kinda spatial patterning
[00:08:33.890]on this eastern portion of the Great Plains.
[00:08:35.960]We're seeing a lot more fires occurring
[00:08:37.830]under near-normal and moist conditions.
[00:08:40.770]When we shift over
[00:08:41.603]to this western portion of the Great Plains
[00:08:43.330]where we're seeing more increases in large wildfire,
[00:08:46.800]we see that those fires are more likely to be occurring
[00:08:49.580]under severe, moderate, and extreme drought conditions.
[00:08:53.337]And we can look at this another way
[00:08:54.670]if we break this down by fire frequency relative to PDSI,
[00:08:58.800]the Palmer Drought Severity Index,
[00:09:00.690]which is our drought indicator.
[00:09:02.470]You can see I've got these color codes
[00:09:04.590]down here on the bottom,
[00:09:06.200]and you can see that we definitely have
[00:09:08.870]a lot more frequent fires under drier conditions,
[00:09:11.790]particularly under moderate and severe drought conditions.
[00:09:15.440]So clearly weather and climate are gonna be playing
[00:09:18.360]a huge role in our fire distribution in the Great Plains,
[00:09:21.530]and it's something that we need to look into further.
[00:09:25.670]But a lot of my research has focused specifically on fuels.
[00:09:29.210]One reason is because for individual landowners,
[00:09:32.040]it's a lot easier for them
[00:09:33.240]to manage for fuels on their property
[00:09:36.350]rather than trying to manage for global climate.
[00:09:39.510]But the other thing is that we've seen massive changes
[00:09:42.810]in fuels here in the Great Plains over the last century,
[00:09:46.480]in addition to fragmentation and agriculture development.
[00:09:51.400]We've also seen this large shift
[00:09:53.980]from grassland to woody vegetation in a number of areas.
[00:09:58.090]And this has really been associated
[00:10:00.250]with the removal of fire from the Great Plains
[00:10:02.910]that's leading to all of this woody encroachment
[00:10:05.221]into grassland areas.
[00:10:07.320]Basically, historically, if we had frequent fires
[00:10:09.980]moving through grasslands,
[00:10:11.260]they would've killed woody seedlings
[00:10:12.980]that were trying to establish in a grassland,
[00:10:16.640]and it would prevent woody establishment and growth.
[00:10:21.630]So I just want to give you an example here,
[00:10:23.430]looking at Nebraska,
[00:10:24.720]in terms of patterns of woody encroachment for this region.
[00:10:28.580]If you look on the left here, we've got different plots
[00:10:32.610]from all of our conservation landscapes here in Nebraska,
[00:10:36.530]and in each of these plots, we're looking at the change
[00:10:39.570]in woody cover and hectares over time.
[00:10:42.170]So on our x-axis, we're looking at time from 2000 to 2017,
[00:10:47.340]on our y-axis, we've got woody cover in hectares.
[00:10:50.560]And you can see
[00:10:51.640]in the majority of our conservation landscapes,
[00:10:54.070]we're seeing an increase in woody cover.
[00:10:57.150]This can be looked at another way as well.
[00:10:58.860]If we look at this map that we've gotten here,
[00:11:01.460]excuse me, you can see all of our rangelands here
[00:11:05.210]are color-coded, all of our rangeland areas in Nebraska,
[00:11:09.040]and everywhere that's red is an area where we found increase
[00:11:12.920]in percent woody cover through time between 2000 and 2017.
[00:11:18.140]Blue areas are where we saw a decline.
[00:11:20.360]So you can see that in Nebraska here over the last 20 years,
[00:11:24.450]we're seeing a major shift towards woody vegetation.
[00:11:28.850]And this isn't just happening, kind of,
[00:11:31.990]in remote areas or conservation landscapes,
[00:11:36.110]we're also seeing it in our managed areas,
[00:11:38.700]and areas where we thought might be less susceptible
[00:11:41.750]to woody encroachment.
[00:11:42.840]So we did an assessment looking in the Nebraska Sandhills,
[00:11:46.440]and we were tracking eastern redcedar establishment
[00:11:50.190]from windbreaks, and its encroachment
[00:11:52.160]into our our rangeland systems and near our farmsteads.
[00:11:55.790]And what we found is that about 25% of windbreaks
[00:11:58.940]that we assessed actually had established eastern redcedar
[00:12:02.000]spread in the Nebraska Sandhills.
[00:12:05.490]So I was really interested to understand
[00:12:08.160]how woody encroachment and other land use changes
[00:12:12.590]might be influencing wildfire patterns.
[00:12:15.360]And so in this map here,
[00:12:17.020]we're looking at the five different land use types
[00:12:20.280]that we assessed in the study.
[00:12:21.710]We were looking at herbaceous vegetation, woody vegetation,
[00:12:24.810]crops, pasture and hayfields, and developed areas.
[00:12:28.210]We've got all our wildfire perimeters that we assess.
[00:12:30.580]This was from 1993 to 2014, these wildfires.
[00:12:36.770]And what we wanted to see is
[00:12:38.270]if wildfires are burning disproportionately more
[00:12:41.410]within certain land use types.
[00:12:44.880]And so if we look for the Great Plains as a whole,
[00:12:48.350]what you can see is that we have really low wildfire risk
[00:12:51.650]in crops, pasture, hayfields, and developed areas,
[00:12:54.650]whereas we have higher wildfire risk
[00:12:56.620]in herbaceous and woody vegetation.
[00:12:58.860]Now, the really interesting thing about this
[00:13:01.590]is that we see that woody vegetation
[00:13:03.730]actually holds the larger,
[00:13:05.750]or the highest large wildfire risk,
[00:13:07.839]while herbaceous vegetation is generally more flammable,
[00:13:11.200]it's more pyrogenetic.
[00:13:13.610]We are seeing that woody vegetation
[00:13:15.330]is hosting the highest wildfire risk.
[00:13:18.590]When we break this down and look at the relationship
[00:13:22.080]between the amount of cover of herbaceous
[00:13:24.590]and woody vegetation on an individual landscape,
[00:13:27.570]and how that affects large wildfire risk,
[00:13:30.440]what we can see is that you need about 60% of your landscape
[00:13:34.730]to be covered in herbaceous vegetation
[00:13:37.350]before we see this spike in large wildfire risk.
[00:13:40.710]So a relatively contiguous herbaceous cover
[00:13:46.150]across your landscape.
[00:13:48.120]Whereas when we look at the same thing for woody vegetation,
[00:13:51.180]we see you only need about 20% of your landscape
[00:13:54.260]covered in woody vegetation
[00:13:55.780]before we see this increase in large wildfire risk.
[00:13:58.930]So only small amounts of woody encroachment
[00:14:02.080]within these areas before we're seeing
[00:14:04.180]an increased large wildfire risk for that area.
[00:14:08.590]When we broke this down,
[00:14:09.720]and looked again at those different ecoregions,
[00:14:11.900]I mentioned in the Great Plains,
[00:14:13.220]you can see there's clearly a lot of variability here,
[00:14:16.920]but when we isolate the ecoregions
[00:14:19.360]where we had the greatest increases in wildfire number
[00:14:22.970]and total hectares burned,
[00:14:24.840]we can see that in almost all of these ecoregions,
[00:14:27.810]woody vegetation by far
[00:14:29.540]held the greatest large wildfire risk.
[00:14:34.420]And recall that I mentioned
[00:14:36.190]that the Great Plains' fire regime is now really dominated
[00:14:40.600]by our ability to suppress fire.
[00:14:43.010]And so the reason why we think we're seeing more wildfires
[00:14:47.280]occurring in woody vegetation,
[00:14:49.140]even though we know that grassland vegetation
[00:14:51.900]is generally more pyrogenic,
[00:14:54.620]is because there's a pretty big difference
[00:14:57.130]in our ability to suppress fires
[00:14:59.220]that are occurring in grassland vegetation
[00:15:01.200]compared to woody vegetation.
[00:15:03.200]And you can see this pretty clearly with this image
[00:15:05.290]I've stolen from Dirac Twidwell.
[00:15:07.700]On the left here, you can see flame links
[00:15:10.270]that are occurring in herbaceous vegetation,
[00:15:13.230]and when you look on the right,
[00:15:14.470]here you can see the flame links that are created
[00:15:16.870]when an eastern redcedar tree is alight.
[00:15:19.340]And so obviously it's gonna be a lot more difficult for us
[00:15:21.810]to control and suppress fires in this woody vegetation
[00:15:26.090]compared to the herbaceous vegetation
[00:15:28.010]under the same conditions.
[00:15:31.040]So basically what we're learning from this
[00:15:34.080]is that removing fire from the Great Plains
[00:15:36.197]has really helped to promote woody encroachment,
[00:15:38.784]and woody encroachment
[00:15:40.260]seems to be helping fuel more wildfires.
[00:15:42.920]So we kinda have this cyclical pattern here,
[00:15:45.330]and it makes me think of this quote,
[00:15:47.487]"Can't live with it. Can't live without it."
[00:15:50.130]Over the last century, we really thought,
[00:15:52.140]we can't live with fire,
[00:15:53.520]let's try to remove it as much as we can from the landscape,
[00:15:57.030]and it's turning out that we really can't live without fire.
[00:16:00.140]If we remove prescribed fire
[00:16:01.717]and the application of more controlled burns
[00:16:04.720]on the landscape, we're seeing this shift
[00:16:06.680]towards more of a wildfire dominated regime.
[00:16:10.290]And so I wanna just put a question mark
[00:16:12.930]beside the "Can't live with it".
[00:16:15.710]And that's because we've seen that people can live
[00:16:18.970]and co-exist and thrive with fire here in the Great Plains.
[00:16:23.300]Just again, as a reminder, indigenous land stewardship
[00:16:26.880]utilized fire frequently across the Great Plains
[00:16:30.530]to maintain grassland systems
[00:16:32.540]for thousands and thousands of years.
[00:16:34.772]And we're starting to see an uptick
[00:16:38.210]in people embracing burn culture in the Great Plains
[00:16:41.930]to help mitigate against woody encroachment
[00:16:45.190]and large wildfire risks.
[00:16:46.810]So, as an example, in the Loess Canyons of Nebraska,
[00:16:50.650]a location that's seen a large amount of woody encroachment
[00:16:53.970]into their rangeland systems,
[00:16:55.700]we're seeing landowners band together
[00:16:57.850]and start applying prescribed burns
[00:17:00.250]across a lot of their landscape.
[00:17:02.360]So in the map in this corner here,
[00:17:04.530]you can see the outline of the Loess Canyons,
[00:17:06.910]and all of these orange polygons in the map
[00:17:09.340]represent prescribed burn perimeters
[00:17:11.910]that were applied by landowners in the Loess Canyons
[00:17:14.900]over the last, around 20 years.
[00:17:19.040]So why are we not seeing more prescribed fire
[00:17:21.940]on the landscape?
[00:17:22.930]Well, there's a lot of concerns
[00:17:25.640]around prescribed fire that people have.
[00:17:28.080]So I'm just gonna talk about a few of these,
[00:17:30.240]and try to kinda cancel out some of the fears of fire
[00:17:34.660]that some of us might hold.
[00:17:36.410]The first one that a common concern is for people is that
[00:17:39.670]prescribed fire, and fire in general, is quite risky.
[00:17:44.010]And so I'm gonna steal an example
[00:17:45.950]from Dirac Twidwell's paper that he published back in 2015,
[00:17:50.490]where he was looking at the rate of fatal injuries
[00:17:53.400]associated with different surrogates for range management.
[00:17:58.410]And I want to focus particularly on two here,
[00:18:01.450]looking at firefighters over here on the far left,
[00:18:05.170]and logging workers over here on the far right.
[00:18:07.540]And firefighters, he uses, really,
[00:18:09.910]as a surrogate for fire management,
[00:18:12.720]obviously a little bit more extreme,
[00:18:14.270]'cause firefighters are generally dealing with fires
[00:18:16.360]that are out of our control, whereas fire management
[00:18:18.667]is dealing with prescribed planned fires.
[00:18:21.530]And then logging workers can be compared
[00:18:24.440]to this idea of mechanical tree removal.
[00:18:26.430]So a lot of us
[00:18:27.560]are currently applying mechanical tree removal
[00:18:30.010]to try to get rid of eastern redcedar trees
[00:18:32.850]and woody encroachers,
[00:18:34.429]it's a lot more costly method,
[00:18:36.120]but a lot of people perceive this as a more safe method
[00:18:38.730]than using prescribed fire.
[00:18:40.480]And so you can see
[00:18:41.360]when we compare the rates of fatal injuries,
[00:18:44.260]clearly this perception is a little bit off.
[00:18:46.590]We see a lot lower rate of fatal injuries for firefighters
[00:18:49.810]compared to logging workers.
[00:18:52.420]We also know that the number of fatal injuries associated
[00:18:55.560]with wildfire is much higher than prescribed fire.
[00:18:58.900]So if we choose to use prescribed fire proactively
[00:19:02.130]to help prevent wildfires,
[00:19:04.230]we should have a much safer outcome
[00:19:06.440]than waiting for wildfires on our landscape.
[00:19:10.160]Another common concern people have with fires
[00:19:12.450]is that fire can drive losses in grasses.
[00:19:15.360]And a number of people have concerns associated
[00:19:17.800]specifically with desertification driven by fire.
[00:19:21.000]So this is when we shift from grasslands
[00:19:23.341]into a bare ground state.
[00:19:25.460]So if we have a very hot fire under drought conditions,
[00:19:28.600]there's concern that the grasses
[00:19:29.840]are not going to be able to reestablish.
[00:19:31.410]And we see a lot of people applying seeding to the landscape
[00:19:34.390]after fire to try to help grasses regenerate.
[00:19:38.410]And so we wanted to see how grasses are regenerating
[00:19:42.450]across the Great Plains, relative to fire,
[00:19:45.330]and we wanted to use extreme examples.
[00:19:47.280]So we, again, went back to our wildfire perimeter data,
[00:19:51.400]and we wanted to track how vegetation was responding
[00:19:54.700]to these wildfires across the Great Plains.
[00:19:57.920]And so what we did here, you can see in these plots,
[00:20:01.040]we're looking at the relationship
[00:20:02.470]between mean cover and time since fire.
[00:20:06.620]I've got two different cover types here.
[00:20:09.390]We've got perennial forbs and grasses,
[00:20:11.300]and then we're also gonna look at bare ground as well.
[00:20:14.030]So in these plots, this red bar here
[00:20:16.650]represents the time of the fire,
[00:20:19.360]so when the fire occurred,
[00:20:21.210]and then this gray bar is representing
[00:20:23.280]our pre-fire range of variation.
[00:20:26.030]So we looked 10 years before each fire,
[00:20:28.830]and we wanted to see how much variability
[00:20:31.617]in perennial forbs and grass cover,
[00:20:33.750]or bare ground cover, there was,
[00:20:35.714]before the fire occurred to kinda get a pre-fire,
[00:20:39.970]like I said, a range of variation
[00:20:41.390]that occurred before the fire.
[00:20:43.100]We wanted to track and see if our vegetation
[00:20:46.470]returned to this pre-fire range of variation,
[00:20:48.610]which would indicate recovery.
[00:20:50.620]And so you can see pretty clearly here
[00:20:52.550]with perennial forbs and grasses immediately following fire.
[00:20:56.350]We see this drop outside of our pre-fire range of variation,
[00:20:59.680]but within a year, we're already back
[00:21:01.450]into our pre-fire range of variation
[00:21:03.190]for perennial forb and grass cover
[00:21:05.140]when we look at all fires averaged across the Great Plains.
[00:21:09.350]Similarly with bare ground,
[00:21:11.050]we see this corresponding spike in bare ground cover
[00:21:14.330]the year of the fire, and we see that rapidly return
[00:21:16.890]to our pre-fire range of variation.
[00:21:18.990]So basically this response was so consistent
[00:21:21.200]across fires in the Great Plains
[00:21:23.260]that we could detect it at this biome level.
[00:21:27.320]We also broke this down and looked at smaller scales,
[00:21:29.900]so again, we're looking at our individual ecoregions here,
[00:21:33.050]and you can see again, rapid recovery of perennial forbs
[00:21:35.927]and grasses following fire,
[00:21:37.920]and actually in a lot of cases,
[00:21:39.190]we don't even see that fire drives a decline in cover
[00:21:42.950]below that pre-fire range of variation.
[00:21:46.380]We also went down even further
[00:21:47.990]to individual wildfires and individual pixels as well,
[00:21:51.720]so a 30 by 30 meter area, to assess vegetation recovery,
[00:21:55.490]and we saw rapid returns to pre-fire range of variation.
[00:21:58.680]So I'll give you an example here,
[00:22:00.530]from the Region 24 Complex fire that burned
[00:22:03.230]in the Nebraska Sandhills back in 2012,
[00:22:06.490]and the Nebraska Sandhills is perceived as an area
[00:22:09.540]that's quite sensitive to fire,
[00:22:11.710]particularly under extreme drought conditions.
[00:22:14.550]And this fire burned
[00:22:15.850]under extreme drought conditions back in 2012.
[00:22:18.410]And we can see this rapid recovery
[00:22:20.520]of perennial forbs and grasses.
[00:22:24.900]In contrast, we see that trees are quite sensitive to fire.
[00:22:28.900]So we can look at an example here,
[00:22:30.450]the Northwestern Great Plains ecoregion.
[00:22:32.910]At the ecoregion scale, we detected a persistent decline
[00:22:37.110]in tree cover following wildfires.
[00:22:39.330]We see this pattern again, when we go to smaller scales,
[00:22:41.670]if we look at the wildfire scale or a local scale as well.
[00:22:46.360]We can also see the ability of fire to remove trees
[00:22:49.280]from a landscape if we look at this.
[00:22:52.140]That paper I was mentioning before,
[00:22:53.960]that was led by Dylan Fogarty,
[00:22:55.860]where we tracked changes in woody vegetation cover
[00:22:59.440]through time between 2000 to 2017.
[00:23:02.780]In these maps here, everywhere that's blue
[00:23:04.540]is where we've lost woody vegetation cover.
[00:23:07.037]And we've outlined here, wildfire perimeters in dark red.
[00:23:11.030]And so you can see the association
[00:23:12.530]between wildfire perimeters and the loss of woody cover.
[00:23:17.140]But it's not just wildfires that are driving declines
[00:23:20.180]in woody vegetation.
[00:23:21.520]We can also see that as well
[00:23:23.410]when we look at the prescribed fires,
[00:23:25.090]if we go back to the Loess Canyons again.
[00:23:27.310]So here, all of these black outlines
[00:23:29.920]are perimeters of our prescribed fires,
[00:23:32.780]and you can see the effectiveness of these fires
[00:23:35.190]at either preventing further woody encroachment
[00:23:38.820]into the prescribed fire perimeter,
[00:23:40.710]or we see that it's driving losses
[00:23:42.420]in woody vegetation cover.
[00:23:45.200]And we tracked tree cover through time in the Loess Canyons,
[00:23:49.100]we actually saw this plateau
[00:23:51.560]in the increasing amount of tree cover in that region,
[00:23:54.300]and we associate this with an increased amount
[00:23:56.820]of prescribed fire on that landscape.
[00:24:00.940]So to sum up with this,
[00:24:02.410]what we know is that prescribed fire can help us
[00:24:05.420]to fight increasing wildfire
[00:24:07.510]by reducing fuel buildup in grasslands.
[00:24:10.490]It also can prevent woody encroachment in grasslands,
[00:24:13.390]and it can help to remove woody vegetation
[00:24:15.880]in invaded grasslands.
[00:24:17.080]So this is a really great method for us
[00:24:19.760]to try to reduce large wildfire risks,
[00:24:22.150]which we're seeing increasing across the Great Plains.
[00:24:25.850]We know that prescribed fire can be used more safely
[00:24:29.000]than other more costly options,
[00:24:31.010]like mechanical field treatments,
[00:24:33.420]and we also know that using prescribed fire is a lot safer
[00:24:37.150]than waiting for wildfires to burn on our landscape.
[00:24:41.470]And so I think it's time,
[00:24:43.010]as we see this increasing amount of wildfire
[00:24:45.540]in the Great Plains,
[00:24:46.390]that we start to embrace more of a fire culture.
[00:24:50.820]In order to coexist with fire,
[00:24:52.750]the best path forward for us is to embrace prescribed fire,
[00:24:57.180]and embrace the fact that fire belongs
[00:24:59.070]on our Great Plains landscapes.
[00:25:02.045]With that, I'd just like to thank some of the funders
[00:25:04.580]that helped support this work.
[00:25:06.400]Of course, thank the department for having me,
[00:25:08.700]and I'd be happy to answer any questions
[00:25:10.920]that you might have.
[00:25:12.280]Thanks, Tori.
[00:25:13.113]That was really, really good.
[00:25:16.200]So Tori, with everything you've done,
[00:25:20.900]what are, like, maybe next steps for looking at fires
[00:25:25.610]across the western rangelands,
[00:25:27.890]what are your, maybe, next research priorities?
[00:25:31.990]Well, for me,
[00:25:32.823]one thing that I do want to look into more
[00:25:34.615]is the relationships between climate vegetation and fire.
[00:25:41.160]I think that's something
[00:25:41.993]that we really need to couple together.
[00:25:44.090]There's a lot of information
[00:25:45.260]that we still need on those patterns.
[00:25:48.980]I'd also really like to investigate the relationships
[00:25:52.550]with changing wildfire out West,
[00:25:55.260]and how that's kinda moving into the Great Plains.
[00:25:58.090]I'm kinda interested to see,
[00:25:59.310]because we've got this western,
[00:26:02.240]kind of, edge of the Great Plains
[00:26:03.710]where we're seeing a lot more increasing wildfire,
[00:26:05.840]and I'd like to understand if that's linked to changes
[00:26:08.520]in the western US as well.
[00:26:11.050]Maybe I could just talk, maybe,
[00:26:12.310]about the interactions you've had with media about fire,
[00:26:17.950]and just your experience with that.
[00:26:21.260]What do you think is the thing
[00:26:23.130]that drives people's imaginations with fire research
[00:26:27.590]and fire on the landscape the most?
[00:26:31.040]I mean, I think there's a lot of concern
[00:26:32.880]about fire, rightfully so.
[00:26:38.887]You know, if you look at this picture that I have here,
[00:26:41.560]it's kinda scary,
[00:26:43.520]but I think the big thing that we need to push for
[00:26:48.700]is the understanding that, you know,
[00:26:51.020]fire can be used safely, and in a controlled manner,
[00:26:54.260]and it's not a negative thing.
[00:26:57.560]So, you know, we have Smokey the Bear,
[00:27:00.200]and all of these fire prevention,
[00:27:04.290]outreach pieces, and, you know,
[00:27:07.670]I think from a media point of view,
[00:27:10.210]there's a lot of doom and gloom about increasing wildfire.
[00:27:14.360]And I think it's important to recognize the benefits of fire
[00:27:17.620]and how we can use fire, and co-exist with fire
[00:27:21.700]in a safe manner in these landscapes.
[00:27:24.770]There is a question in the chat
[00:27:26.550]from Erin Scheffler,
[00:27:29.257]"How do you think the initial burn of the existing trees
[00:27:34.497]"in these landscapes could be managed effectively?"
[00:27:38.620]So, Erin, are you speaking about the tree skeletons
[00:27:44.100]that exist after a fire or?
[00:27:46.700]Yeah, the existing skeletons could be fine too.
[00:27:49.390]I just didn't, it seems like there's so many trees already,
[00:27:53.930]but like, it would be kind of unmanageable
[00:27:55.700]to start the program, you know?
[00:27:58.760]Right, well, it depends on the area,
[00:28:00.610]I mean, the Loess Canyons is a really great example.
[00:28:04.670]They use something, I think this is what they say is,
[00:28:07.240]tuck and stuff, is that right,
[00:28:09.250]where they'll cut other eastern redcedars down
[00:28:12.300]around the perimeter and stuff those
[00:28:14.590]underneath standing trees to help move the fire
[00:28:18.010]from the ground into the tree.
[00:28:20.440]Because it is true once cedars establish, it is quite dense.
[00:28:26.069]You know, all of the herbaceous fuels underneath
[00:28:29.530]aren't there to carry the fire through anymore,
[00:28:31.480]and so you do sometimes need those extra management steps
[00:28:34.310]to help move a fire up into the canopy
[00:28:37.230]to kill the cedar trees. Cool, thank you.
[00:28:40.770]Thanks Thanks, Erin.
[00:28:42.340]We have Dan Yude. Yeah, thanks, Tori.
[00:28:45.630]I was just, you know,
[00:28:48.560]you were mentioning there at the end,
[00:28:50.300]looking at maybe comparing Great Plains wildfire activity
[00:28:57.460]with, you know, further west, maybe the Great Basin,
[00:29:01.280]or further, the entire western US.
[00:29:04.310]And I was also thinking about, you know,
[00:29:06.180]it was about a year ago that Australia
[00:29:08.950]was really in the midst of those massive wildfires,
[00:29:13.550]and there was so much about that in the media,
[00:29:17.600]but then of course COVID came on the scene,
[00:29:20.982]and then all of a sudden
[00:29:22.090]that kinda dominated much of that news,
[00:29:24.880]but I guess I just never really followed up
[00:29:29.920]on some of the Australian impacts.
[00:29:34.220]I mean, I guess I'm asking
[00:29:37.290]if you could speculate on globally,
[00:29:41.090]moving from even a North American perspective
[00:29:43.830]to a global perspective,
[00:29:45.720]are there any sort of similarities there,
[00:29:49.080]in perhaps regions of Australia
[00:29:52.210]that would be more similar to the Great Plains
[00:29:55.100]that you can make connections with?
[00:29:58.200]I honestly don't, I am not as familiar,
[00:30:00.870]or I can't recall right now, all of the drivers
[00:30:03.820]about why that wildfire season was so bad in Australia,
[00:30:07.470]I'm assuming it was linked to changing climate,
[00:30:10.850]I think there was a drier period,
[00:30:14.350]and obviously there's changes.
[00:30:16.000]I think, you know, in most locations you see,
[00:30:18.590]if there's more precipitation in a certain area,
[00:30:20.510]you get fuel buildup,
[00:30:21.760]and then you have a more extreme drought period,
[00:30:24.140]and then it's easier for fuels to ignite and burn.
[00:30:26.890]You have a greater fuel buildup.
[00:30:28.470]Thanks so much.

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Coexisting with Fire in Rangelands

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