Reducing Eastern Redcedar Encroachment in Grasslands

Dillon Fogarty Author

08/29/2022 Added

6 Plays

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Dillon Fogarty discusses methods to reduce eastern redcedar encroachment in grassland systems.

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[00:00:00.000](warm music)
[00:00:07.380]Dillon Fogarty is a PhD candidate and coordinator
[00:00:10.500]for the Working Lands Conservation
[00:00:12.930]and the Department of Agronomy and Horticulture at UNL.
[00:00:17.610]Prior to coming to Nebraska in 2017,
[00:00:19.950]he received his master's degree
[00:00:21.810]in natural resource ecology and management
[00:00:23.910]from Oklahoma State in 2016,
[00:00:26.850]his bachelor's in biology
[00:00:29.610]from Bemidji State in Minnesota in 2013.
[00:00:33.540]Dillon's work is centered around
[00:00:36.000]what makes rangelands vulnerable
[00:00:38.430]to woody plant invasion and how management actions
[00:00:41.070]and policies can be used to reduce that vulnerability
[00:00:44.760]and keep rangelands productive.
[00:00:46.620]His work seeks to inform solutions
[00:00:48.690]for rangeland conservation
[00:00:50.640]through research extension and teaching.
[00:00:53.130]He recently co-authored an extension guide
[00:00:55.320]for managing woody encroachment
[00:00:57.000]and has had over 19,000 copies distributed
[00:01:00.330]throughout the Great Plains
[00:01:01.800]and that serves as a foundation
[00:01:03.810]for the new Great Plains Grasslands Initiative launched here
[00:01:07.410]in Nebraska.
[00:01:08.730]I will turn the floor over to Dillon.
[00:01:10.770]It looks like he's got some materials to show you as well.
[00:01:13.230]So thank you.
[00:01:15.330]Thank you.
[00:01:16.163]And thanks, everyone, for being here.
[00:01:17.430]It's a pleasure to be with you all today in the Sandhills
[00:01:20.000]to talk about this important issue.
[00:01:24.480]What I'm gonna do today with my talk is I'm gonna talk
[00:01:27.690]about a guide we developed last year in partnership
[00:01:31.500]with extension faculty from across the Plains
[00:01:34.200]for reducing woody encroachment.
[00:01:35.970]And so what this guide does is
[00:01:38.130]it outlines the first strategy for taking the tools
[00:01:41.850]in our range management toolbox and applying them
[00:01:44.340]to woody encroachment.
[00:01:45.900]So before strategies have focused
[00:01:48.300]on how to use different tools,
[00:01:51.150]what this guide does is it puts those tools together
[00:01:53.970]and shows how they can be used as part of a broader strategy
[00:01:56.970]for managing encroachment.
[00:02:00.840]So I wanted to start here
[00:02:03.690]with why we care about woody encroachment,
[00:02:05.670]why it matters.
[00:02:07.590]And so this is long-term data from Sonora Research Station
[00:02:10.410]in Texas for juniper species down there.
[00:02:14.010]We see the same trend for every juniper species
[00:02:17.040]in the Great Plains.
[00:02:18.390]And what we have is,
[00:02:20.250]we can't see the Y axis perfectly,
[00:02:22.170]but we have a loss in livestock production over time.
[00:02:26.280]As grasslands transition
[00:02:28.740]to a fundamentally different state dominated
[00:02:31.110]by conifer trees,
[00:02:33.810]we see this gradual,
[00:02:36.990]what starts out gradual becomes a rapid loss
[00:02:41.490]in forage resources resulting in, on average,
[00:02:44.010]75% reduction in forage production in the pasture.
[00:02:53.730]Now, that's based on data collected over 20 years ago.
[00:02:58.740]With advances in remote sensing technology,
[00:03:01.590]we can now track losses in forage production
[00:03:05.070]across every 30-meter pixel for the entire Western US.
[00:03:09.990]So think of a baseball diamond.
[00:03:11.730]We can now track impacts to forage production due
[00:03:14.970]to woody encroachment at that scale
[00:03:16.500]across the entire Western US.
[00:03:19.200]In Nebraska, in 2019 alone,
[00:03:22.380]we lost 419,000 tons of forage production
[00:03:26.370]to woody encroachment.
[00:03:28.530]That uses a 1990 baseline,
[00:03:30.930]but it shows how increases in tree cover
[00:03:34.350]since 1990 have impacted forage production in Nebraska.
[00:03:39.144]419,000 tons.
[00:03:41.910]If we see the trend over time, again, that 1990 baseline,
[00:03:47.340]stable for a while,
[00:03:49.350]once we started losing production,
[00:03:51.390]it has continued to go down.
[00:03:54.390]This is the trajectory that we're on.
[00:03:57.630]Right now, we've lost a small percentage
[00:03:59.460]of our overall forage,
[00:04:01.800]but we know the long-term trajectory for this is up
[00:04:05.250]to a 75% reduction in forage biomass.
[00:04:14.400]So we don't really communicate very well
[00:04:16.230]how much 419,000 tons of forage is.
[00:04:20.910]So we've broken it down into round bales.
[00:04:24.000]It's about 700,000 1,200-pound round bales.
[00:04:28.410]If we stack those up and put 'em on the highway,
[00:04:31.560]that would be more
[00:04:32.393]than the distance from Kansas City to Denver,
[00:04:36.090]enough for it to support almost 90,000 cows
[00:04:38.850]for a year based on animal units.
[00:04:46.530]Unfortunately,
[00:04:47.363]the impacts aren't restricted to just forage production.
[00:04:52.050]When we have a transition from a grassland
[00:04:54.480]to an eastern red cedar-dominated state, a juniper woodland,
[00:04:58.590]we see impacts of livestock production.
[00:05:01.380]Grassland wildlife collapses.
[00:05:03.780]We have increased wildfire hazard due
[00:05:06.450]to the sheer flame lengths that can be generated
[00:05:09.390]while cedar trees are combusting
[00:05:11.040]and the difficulty in suppressing those fires.
[00:05:14.100]Additionally,
[00:05:14.933]we have research that's looked at wildfire spread,
[00:05:17.700]so how far embers can be transported in grassland fires
[00:05:22.500]versus fires that are consuming juniper woodland areas.
[00:05:26.550]And we see much longer transport distances
[00:05:29.100]and potential for large wildfires.
[00:05:32.460]We see impacts to human health.
[00:05:34.500]So there's actually relatively new research out of Oklahoma
[00:05:38.550]that shows encroached grasslands have increased prevalence
[00:05:42.660]of tick and mosquito-born diseases.
[00:05:45.900]So things like West Nile virus
[00:05:49.050]and then some of the tick-transmitted pathogens as well.
[00:05:53.550]So we're seeing increased prevalence in those.
[00:05:55.500]In addition, eastern red cedar contributes to hay fever.
[00:06:04.170]It produces a lot of pollen
[00:06:05.550]that's distributed through the air column,
[00:06:07.740]and people can be very sensitive to it.
[00:06:10.770]So we see some impacts to health.
[00:06:13.620]We see impacts to water supply,
[00:06:15.570]depending on where you're at in the Great Plains.
[00:06:17.280]This has been studied in Texas, Oklahoma, Kansas, Nebraska,
[00:06:22.860]and impacts are gonna depend on where you're at.
[00:06:26.400]But in the Sandhills,
[00:06:27.330]we've found reduced aquifer recharge under areas
[00:06:31.020]that have been converted to a red cedar woodland.
[00:06:33.990]In Oklahoma, they use modeling to show
[00:06:37.020]how encroachment can reduce stream flow.
[00:06:41.460]We see impacts to endangered species like
[00:06:43.560]the American burying beetle that has strongholds
[00:06:46.860]in the Nebraska Loess Canyons and the Sandhills.
[00:06:49.980]We see impacts to school funding.
[00:06:52.290]So the Board of Education Lands and Funds in Nebraska,
[00:06:55.680]as the largest landowner in the state,
[00:06:57.480]owns almost a million acres of rangeland.
[00:07:01.320]Profits go to K through 12 education.
[00:07:04.470]As they spend more money managing red cedar
[00:07:07.680]and this problem,
[00:07:09.480]that's less money going to fund public education.
[00:07:13.084]We're actually talking
[00:07:14.550]with the Board of Education Lands and Funds
[00:07:17.100]how we can more effectively
[00:07:19.710]and economically manage cedar on those lands.
[00:07:22.770]And so I wanted to bring this up
[00:07:24.480]as why this is such an important issue
[00:07:28.860]before we dive into some of the management strategies
[00:07:32.280]for dealing with the problem.
[00:07:35.130]Okay.
[00:07:35.963]Well, I wanna step back just one more time
[00:07:38.190]and think about why is this happening?
[00:07:41.580]We have not been dealing with red cedar encroachment forever
[00:07:45.150]in the Great Plains.
[00:07:47.280]Places like Nebraska have been dealing with it not as long
[00:07:49.710]as Kansas or Oklahoma.
[00:07:51.450]So I wanna step back and talk a little bit
[00:07:53.670]about why we're dealing with encroachment today.
[00:07:58.590]Bear with me.
[00:07:59.760]I'm gonna walk us through a vulnerability framework
[00:08:02.790]to help us understand
[00:08:04.860]how grassland vulnerability has changed to encroachment.
[00:08:10.140]Right now, I wanna focus on risk.
[00:08:11.640]So we have risk is driven by sensitivity and exposure.
[00:08:17.520]Sensitivity is how fast a grassland's going to transition
[00:08:25.320]to a red cedar-dominated state
[00:08:28.620]in the absence of seeds or propagules.
[00:08:32.040]And so historically,
[00:08:34.260]the Great Plains had very low sensitivity to encroachment.
[00:08:37.740]We had a fire return interval.
[00:08:39.300]Fire was very common throughout the Great Plains.
[00:08:42.000]Actually, through human ignitions,
[00:08:45.150]we had very frequent fire every two to 10 years,
[00:08:48.180]depending on where you're at in the Great Plains.
[00:08:51.300]Fire limits woody plants.
[00:08:53.550]So as the eastern red cedar spread,
[00:08:56.250]the seedlings and even mature trees are very vulnerable
[00:08:59.250]to fire.
[00:09:00.083]Eastern red cedar is one of the most fire-sensitive species
[00:09:03.210]in the Great Plains.
[00:09:04.560]So that frequent burning helped maintain our open,
[00:09:08.100]expansive grasslands and reduced sensitivity
[00:09:12.090]of those grasslands to encroachment.
[00:09:16.830]The second part is exposure.
[00:09:19.170]So for encroachment,
[00:09:21.360]exposure to the problem is the seed source.
[00:09:24.870]For seed-obligate species like eastern red cedar,
[00:09:27.420]they spread via seed.
[00:09:29.610]Historically,
[00:09:32.040]when we hear accounts of the Great Plains,
[00:09:34.230]they talk about an ocean of grass.
[00:09:38.280]No trees.
[00:09:39.113]So we had very little exposure to seed sources.
[00:09:43.620]They're limited to riparian areas,
[00:09:46.350]steep slopes.
[00:09:48.120]By and large,
[00:09:48.953]our grasslands were treeless at large scales.
[00:09:52.020]How both of these factors have changed if we think
[00:09:53.970]about modern-day Great Plains,
[00:09:57.960]through fire exclusion,
[00:09:59.400]we've lost almost all fire in the Great Plains.
[00:10:03.960]Right now, there's a Great Plains fire summit being held
[00:10:06.840]in North Platte with a group of people
[00:10:09.570]that are working to bring prescribed fire back.
[00:10:13.200]But by and large,
[00:10:14.033]we have lost that feedback at large scales
[00:10:19.320]in the Great Plains.
[00:10:21.540]In addition,
[00:10:22.373]we've introduced seed sources throughout the Great Plains.
[00:10:25.500]So not only have we allowed those few scattered seed sources
[00:10:28.950]that would've naturally occurred in the Great Plains,
[00:10:32.850]those have been able to expand into our grasslands.
[00:10:35.250]We've introduced seed sources
[00:10:37.650]through our tree planting program.
[00:10:38.970]So dating back to 1902
[00:10:41.430]when Halsey National Forest was designated
[00:10:44.880]and they started planting trees there,
[00:10:48.390]we've transformed the Great Plains
[00:10:51.960]in terms of grassland exposure to woody plants.
[00:10:57.870]This isn't restricted to the Great Plains.
[00:11:00.030]We're seeing,
[00:11:00.960]so what's resulted is woody and plant invasions
[00:11:03.480]or encroachment.
[00:11:06.000]This is not limited to the Great Plains.
[00:11:07.560]This is actually a global phenomenon happening
[00:11:09.570]in our grasslands.
[00:11:11.370]This is a study conducted in 2017,
[00:11:14.520]and it looked at native tree invasions across the globe
[00:11:17.940]in our grasslands
[00:11:19.800]and basically demonstrated that this is a global problem
[00:11:23.760]in our grasslands.
[00:11:24.593]We're losing grasslands to trees.
[00:11:31.196]If we look at the Western US,
[00:11:32.940]this was a study in 2020 that looked at,
[00:11:36.300]so it used advances in remote sensing technology
[00:11:39.720]so that we can track annual grasses and forbs, perennials,
[00:11:44.070]trees, brush, bare ground,
[00:11:48.750]every year from 1986 to present.
[00:11:53.460]And so they wanted to look at how have rangelands changed
[00:11:55.950]over the past 20 years in this study.
[00:12:00.150]What they've found,
[00:12:00.983]so we have annual forbs and grasses everywhere in blue,
[00:12:04.680]we have a positive trend in annual grasses.
[00:12:08.460]Everywhere in red, we're seeing a decline over time
[00:12:11.428]in that functional group.
[00:12:15.360]What we see is tree cover,
[00:12:19.980]the most substantial change in rangelands
[00:12:21.990]over the last 20 years.
[00:12:24.360]Not bare ground,
[00:12:26.100]not perennials,
[00:12:26.933]not annuals,
[00:12:27.766]tree encroachment.
[00:12:28.599]We see this confirms our concerns over woody encroachment
[00:12:35.490]and highlights the scale of the threat.
[00:12:38.550]If we zoom into the Great Plains,
[00:12:41.520]what you're seeing here is you're seeing
[00:12:46.080]where we have grass-dominated regimes in the Great Plains.
[00:12:48.990]So this data actually tracks conflict.
[00:12:51.900]It pulls in data on grass cover and tree cover.
[00:12:57.510]And instead of showing one or the other,
[00:12:59.490]it shows where they're having a conflict.
[00:13:01.680]So where trees are increasing at the expense of grasslands,
[00:13:05.040]we have red.
[00:13:06.900]Where trees are winning and dominating, we have blue.
[00:13:12.540]And so what we see,
[00:13:13.373]this is the Great Plains in 2000,
[00:13:16.260]by 2018, we're seeing that woody regime,
[00:13:20.340]that woody-dominated area expanding
[00:13:22.650]throughout the Great Plains.
[00:13:25.560]To see it at this scale is pretty remarkable.
[00:13:30.060]We talk about woody encroachment at a pasture scale
[00:13:32.430]or a county scale,
[00:13:33.900]an eco region.
[00:13:35.700]Theoretically, we can have transitions from grass
[00:13:39.330]to woody dominance at any scale,
[00:13:41.460]and we're actually able to see that transition playing out
[00:13:44.190]at the biome scale now.
[00:13:47.550]Dave Engel, retired professor from Oklahoma State,
[00:13:51.240]talked about woody encroachment as the green glacier
[00:13:54.480]because it was the most significant change
[00:13:56.490]to rangeland vegetation in the Great Plains
[00:13:59.880]since the last glaciation.
[00:14:05.310]All right.
[00:14:06.930]So that's a little perspective
[00:14:08.070]on why we're experiencing encroachment,
[00:14:11.550]the scale and extent of it.
[00:14:13.440]Now, what I'm gonna do is I wanna talk about some
[00:14:16.590]of the lessons learned and that have been distilled
[00:14:19.110]in this guide.
[00:14:19.943]If you're interested in a copy,
[00:14:21.390]I've got copies in the back of the room
[00:14:25.500]and additional in the car
[00:14:26.520]if anyone's interested in taking some home.
[00:14:30.990]But what the guide does is
[00:14:32.820]it breaks down key lessons we've learned
[00:14:35.010]over the past 10 years from managing encroachment.
[00:14:37.920]And so I'm gonna break this down into five key points
[00:14:40.920]that I can dive into a little bit deeper on those lessons.
[00:14:46.650]So number one,
[00:14:49.320]avoid denial about woody encroachment.
[00:14:54.420]We often hear that
[00:14:55.980]because woody encroachment hasn't already happened
[00:14:57.930]in a region that it won't happen.
[00:14:59.940]It's a very common attitude across the Great Plains.
[00:15:04.380]And we hear that in the Sandhills too.
[00:15:08.220]When I got here in 2016,
[00:15:09.600]it was it can't happen west of the 100th meridian.
[00:15:13.890]Or it can't happen beyond this level of precipitation.
[00:15:19.710]What we see with invasive species in general is this kind
[00:15:25.560]of dormant period between when they're introduced to an area
[00:15:29.400]and when they start contributing to spread.
[00:15:32.520]And so we actually designed a study
[00:15:33.990]as part of my dissertation research
[00:15:36.030]to look at just where we see woody encroachment
[00:15:39.060]in the Sandhills and that is there something to do
[00:15:43.110]with the 100th meridian
[00:15:44.610]and then as we transition to more arid sites,
[00:15:47.970]do we see an end to encroachment?
[00:15:49.650]We actually wanted to map the end point
[00:15:53.160]to where we see encroachment and then where it stops.
[00:16:00.000]We didn't find an end point in the Sandhills.
[00:16:02.700]We looked. We took over 40 public land sites.
[00:16:05.310]The majority of which had eastern red cedar planted
[00:16:08.040]on the site,
[00:16:09.450]and we asked a few simple questions.
[00:16:12.420]Do we see juvenile trees encroaching?
[00:16:16.920]Do we see adult trees encroaching?
[00:16:19.560]And what that told us is if we see the juveniles,
[00:16:22.920]we're having seed dispersal,
[00:16:24.960]field seeds are germinating into a seedling,
[00:16:28.410]but are they gonna make it?
[00:16:29.850]Is it too dry for them to transition to adulthood,
[00:16:33.060]produce seeds,
[00:16:34.110]and restart the reproduction process?
[00:16:37.695]We found juvenile trees and transitions to adult trees
[00:16:42.180]at every site that we looked at
[00:16:44.490]that had nearby propagule source or seed sources.
[00:16:48.240]So there's a few sites,
[00:16:49.230]I think two sites out of 40 without encroachment.
[00:16:53.700]Those sites were either just under a mile
[00:16:57.660]or over a mile from the nearest seed source.
[00:17:00.930]So instead of precipitation,
[00:17:04.110]the best predictor of are we seeing encroachment or not is
[00:17:09.240]how close are you to a planted seed source.
[00:17:12.360]This is research that it's been reviewed,
[00:17:17.280]it's in the final stages before acceptance.
[00:17:21.750]What we see with precipitation is a better relationship
[00:17:25.740]with the density of encroachment,
[00:17:28.110]so if we see more encroachment in wetter areas compared
[00:17:31.110]to drier areas.
[00:17:34.710]So one of the things that I wanna point out is
[00:17:36.780]when we're seeing small trees,
[00:17:39.630]I don't know if these pictures come through very well,
[00:17:44.640]but those are juvenile cedar trees in herbaceous land,
[00:17:48.180]so what looked for in the study,
[00:17:50.310]when we see those,
[00:17:51.690]that is an early warning
[00:17:53.520]that an area is undergoing encroachment.
[00:17:58.350]And there's no evidence that it's gonna stop
[00:18:00.060]at that juvenile stage,
[00:18:01.650]which brings me to my second point.
[00:18:04.320]Number two, our lesson learned, is don't wait to act.
[00:18:07.620]Be proactive.
[00:18:10.470]When we're seeing seedlings,
[00:18:12.240]that is the most economically optimal time to manage
[00:18:16.140]or before we even get to having seedlings.
[00:18:20.280]So traditionally,
[00:18:23.520]management through cashier programs has focused
[00:18:27.210]on managing this stage and this stage,
[00:18:32.190]mature trees and patches of mature trees.
[00:18:36.060]That's traditionally when those programs kick in
[00:18:39.000]and say we will help a landowner offset the financial cost
[00:18:43.350]of managing the problem.
[00:18:45.493]What we've missed is these younger,
[00:18:49.080]these earlier stages in the encroachment life cycle process.
[00:18:53.520]We've never managed the cone or the seed.
[00:18:57.420]Very few programs have been able to manage seedlings.
[00:19:04.740]What we see here is,
[00:19:05.670]so this shows the density of red cedar
[00:19:10.440]and then the cost of impact.
[00:19:12.570]And what we've plotted here is
[00:19:15.000]different management techniques.
[00:19:17.160]So prescribed fire, hand cutting,
[00:19:20.040]prescribed fire at higher densities.
[00:19:23.310]It's much cheaper if we can act earlier.
[00:19:26.550]In addition,
[00:19:27.383]we avoid impacts that are seen during the later stages
[00:19:29.940]of encroachment.
[00:19:31.620]What our programs have typically focused on is using
[00:19:35.490]heavy mechanical equipment to remove cedars.
[00:19:38.190]It can range from $150 an acre
[00:19:41.340]to over $1,000 an acre,
[00:19:42.720]depending on the terrain and the level of infestation.
[00:19:49.980]So I talked about programs for managing encroachment.
[00:19:56.460]Over the course of the last Farm Bill,
[00:19:57.937]$177 million was spent on brush management.
[00:20:02.460]That primarily represents heavy equipment coming in
[00:20:07.080]and removing dense trees.
[00:20:09.990]Over that same time period,
[00:20:12.630]we saw the problem get worse from 2000 to 2018.
[00:20:19.860]We've managed, in the red,
[00:20:22.140]the majority of those dollars went to the red.
[00:20:24.420]The question we've posed to people is what would happen
[00:20:27.450]if we spent that money in the blue?
[00:20:30.480]That's what this new Great Plains Grassland Initiative
[00:20:34.680]that was mentioned earlier is starting to do.
[00:20:36.870]There's been one launched in Oklahoma, Kansas, Nebraska,
[00:20:39.420]South Dakota.
[00:20:40.410]This initiative is taking that money,
[00:20:47.509]and it's gonna be a more targeted and strategic effort
[00:20:49.860]to spend it in the blue
[00:20:51.810]where we can spread those dollars out over a wider area
[00:20:54.180]and have a bigger impact.
[00:20:58.620]All right, so lesson number three,
[00:21:02.730]we're gonna bring us back to our vulnerability framework,
[00:21:05.250]reduce grassland exposure to seed sources
[00:21:07.440]and manage sensitivity
[00:21:09.150]when those seed sources can't be removed.
[00:21:11.820]So if we remember back to our vulnerability framework
[00:21:15.360]and we're talking about risk,
[00:21:17.070]we have sensitivity and exposure.
[00:21:19.890]So the only way we can reduce a grassland's risk
[00:21:22.920]to encroachment is through one of those two avenues.
[00:21:26.220]And so adaptive capacity,
[00:21:28.710]I like to refer to as the human element here.
[00:21:32.640]It's our ability to change what we do
[00:21:36.300]and adapt to address a problem or a threat.
[00:21:40.290]And so past guidance has focused heavily on sensitivity.
[00:21:45.180]Let's restore fire to maintain our grasslands.
[00:21:50.250]New approaches have started to ask, well,
[00:21:53.550]what would happen if we can reduce exposure
[00:21:57.480]and kinda look at how we can do that.
[00:22:00.480]So I wanna talk about some research
[00:22:03.900]that additionally was a part of my dissertation research
[00:22:06.780]that was actually just accepted
[00:22:08.250]in the Journal of Landscape Ecology.
[00:22:11.730]But we looked at dispersal distances in the Sandhills.
[00:22:16.500]So how far does recruitment occur?
[00:22:20.040]Does seedling recruitment occur
[00:22:21.210]from an existing seed source on the landscape?
[00:22:23.970]And there's this notion that we can't manage exposure,
[00:22:29.310]grassland exposure to seed sources
[00:22:32.280]because there's too many of 'em,
[00:22:33.810]they go too far,
[00:22:36.270]we have no chance at managing dispersal.
[00:22:38.640]Well, what we found was that 95% of recruitment occurred
[00:22:41.910]within two football fields of a seed source,
[00:22:45.180]which tells us we can manage exposure.
[00:22:47.190]We can reduce a grasslands exposure to seed sources
[00:22:53.220]by removing seed sources from the landscape,
[00:22:55.530]and by managing around those seed sources.
[00:22:57.690]So if we can manage two football fields,
[00:22:59.490]we can capture 95% of recruitment.
[00:23:02.940]The other 5% can be managed using less intensive approaches
[00:23:06.840]in areas that are farther from existing seed sources.
[00:23:14.070]Then, the second part,
[00:23:15.300]when a seed source can't be removed,
[00:23:17.760]that's when we can go to sensitivity
[00:23:20.010]and talk about managing that transition zone
[00:23:23.700]that separates the seed source from a treeless grassland.
[00:23:27.270]And so we talk about that as the dispersal
[00:23:29.580]and recruitment zone.
[00:23:32.250]And new best practices in the dispersal
[00:23:34.980]and recruitment zone are to prevent new seed-bearing trees
[00:23:38.910]that perpetuate that encroachment process
[00:23:42.660]and increase grassland vulnerability to encroachment.
[00:23:45.930]And so if we take the stages of encroachment
[00:23:48.570]and map them on a landscape,
[00:23:51.240]I'm talking about this zone right here
[00:23:53.370]where we have incoming seeds and seedlings
[00:23:55.710]but no seed sources yet.
[00:23:57.180]So this is the front lines of encroachment.
[00:23:59.970]This is where we can manage sensitivity.
[00:24:02.910]We think of it as a high-maintenance zone that protects.
[00:24:06.360]If we can keep this in the dispersal and recruitment stage,
[00:24:10.500]if we can create a trap and prevent those trees
[00:24:12.750]from becoming adult seed-producing trees,
[00:24:15.450]we can defend these intact grasslands over here.
[00:24:23.250]Lesson number four is to avoid believing the myth
[00:24:26.970]of restoration and use follow-up management
[00:24:30.060]to get at re-encroachment.
[00:24:32.580]So what I'm showing here is
[00:24:38.160]this is a former eastern red cedar woodland
[00:24:41.010]in the Loess Canyons area just south of North Platte.
[00:24:44.460]It was burned in the 2002 Gothenburg wildfire.
[00:24:48.120]We went back in 2017 and 2018
[00:24:51.690]and measured how it had changed since that initial fire.
[00:24:55.170]So when the fire came through,
[00:24:56.940]you can see some of these big skeletons in here,
[00:25:00.720]complete mortality of red cedar at this patch scale.
[00:25:06.420]This is what's happened with re-encroachment
[00:25:08.670]since that time.
[00:25:09.960]We've had almost a complete return to the woodland state.
[00:25:15.330]Forage has decreased in the area.
[00:25:18.240]It's extremely dense with cedars.
[00:25:20.190]It's difficult to move through.
[00:25:23.160]But it's a really important point
[00:25:24.360]because we've had programs in the past
[00:25:26.010]that only focused on that initial treatment
[00:25:28.530]to come in and remove trees.
[00:25:30.630]Additionally, we hear oftentimes,
[00:25:34.020]especially this year with the wildfires that we've had
[00:25:36.900]that have come through and really knock back the cedars,
[00:25:41.130]we've heard things like,
[00:25:42.247]"Well, I won't have to deal with that anymore.
[00:25:45.637]"That solved the problem."
[00:25:47.970]Well, what we actually see is a re-encroachment process
[00:25:52.290]that's much faster than that initial encroachment process.
[00:25:56.370]So if we have a slow transition to a juniper woodland
[00:25:59.970]or a red cedar state over 40 years,
[00:26:03.720]and we have a wildfire come through
[00:26:05.250]and knock it back completely,
[00:26:07.380]do we have another 40 years?
[00:26:09.697]That was the question we asked.
[00:26:11.430]And what we found is, no, we don't have another 40 years.
[00:26:14.850]This line right here shows re-encroachment,
[00:26:17.910]and this is encroachment.
[00:26:20.070]What this plot shows is the density of trees.
[00:26:23.550]And so with re-encroachment, density spikes.
[00:26:28.650]It returns to pre-treatment levels
[00:26:32.610]within three to four years
[00:26:34.860]and then continues to exceed pre-treatment densities.
[00:26:40.920]Just looking at the time to seedling establishment,
[00:26:45.660]if I can direct your attention over here, we have,
[00:26:48.210]think about three plots, A, B, and C.
[00:26:50.340]One was in the red cedar woodland,
[00:26:52.920]one was on the edge,
[00:26:54.120]and one was over 50 yards from that edge.
[00:26:58.470]How long does it take seedlings to establish
[00:27:00.330]in each of those patches?
[00:27:02.940]One year in the juniper woodland,
[00:27:06.540]four to five on the edge,
[00:27:10.020]and 14 in the grassland.
[00:27:14.010]So by waiting to act and being reactive,
[00:27:17.730]we're actually losing time in our management.
[00:27:21.150]We have to manage a lot more often
[00:27:23.460]once we let something go to a red cedar state.
[00:27:27.000]Even if we restore it,
[00:27:28.020]it's gonna require more to manage to keep it in that grass,
[00:27:30.990]that restored grassland state.
[00:27:33.480]What we have here is red cedar cover.
[00:27:36.930]And so this is re-encroachment
[00:27:39.150]with the initial encroachment process right here.
[00:27:42.720]What we see is for five to eight years,
[00:27:46.530]tree cover's low and stable.
[00:27:49.860]Most of the seedlings are still in the grass layer,
[00:27:52.140]not having an impact really on our cover.
[00:27:56.970]After that period, though, with re-encroachment,
[00:27:59.700]we see that exponential growth period
[00:28:01.830]where the trees come out of the grass
[00:28:03.780]and really start increasing in cover rapidly.
[00:28:07.440]Whereas in the adjacent grassland,
[00:28:09.930]we don't see any increases in cover until after 15 years.
[00:28:18.900]This is the last one I've got for today,
[00:28:21.210]but it could essentially be talked
[00:28:24.300]about the whole presentation and that's have a plan.
[00:28:28.080]We have grazing management plans.
[00:28:30.120]We have drought plans.
[00:28:33.540]Given the increasing risk and vulnerability
[00:28:36.090]of our grasslands to woody encroachment,
[00:28:38.400]we need to start talking about plans
[00:28:40.080]for managing encroachment.
[00:28:42.810]One of the things we break down in the guide is instead
[00:28:46.920]of focusing on the tool that's most convenient
[00:28:50.820]or a favorite tool is using the biological stages
[00:28:54.150]of encroachment as a roadmap
[00:28:55.680]or a blueprint for managing encroachment.
[00:28:58.770]So like I said earlier,
[00:29:00.630]we can map these stages across the landscape
[00:29:05.250]where intact grasslands are represented as grasslands
[00:29:08.880]that have no incoming seed, they're treeless,
[00:29:11.370]they don't have seedlings.
[00:29:13.020]Our dispersal and recruitment zone,
[00:29:14.850]that's the front lines of the encroachment process.
[00:29:18.390]The encroachment stage
[00:29:19.440]where we have mature, seed-bearing trees.
[00:29:22.410]And then, the woodland transition
[00:29:23.640]where we have the most severe impacts.
[00:29:26.790]Each of those stages has different management requirements,
[00:29:30.180]but provide the blueprint
[00:29:31.274]for implementing more strategic approaches
[00:29:35.610]for managing encroachment on our lands.
[00:29:39.600]And so the book dives a lot more into this,
[00:29:45.360]but some of the planning considerations we talk about is
[00:29:48.720]can we partner with our neighbors?
[00:29:51.600]Often, seed sources aren't coming from a single property,
[00:29:54.750]and a property might be vulnerable
[00:29:56.850]to a neighbor or seed source.
[00:30:00.720]The greater area we can partner with,
[00:30:03.540]the better able we are to manage our grasslands
[00:30:06.510]and reduce the risk of encroachment.
[00:30:09.690]What are the management goals?
[00:30:11.190]Our management goal is to stabilize
[00:30:14.040]and conserve our remaining grasslands.
[00:30:15.960]Or is it to actually reverse the encroachment process?
[00:30:18.960]'Cause that requires different approaches to management.
[00:30:24.000]Do plans account for seed sources?
[00:30:26.250]So if we have seed sources on a site,
[00:30:28.290]is there a plan to manage those
[00:30:30.480]and prevent them from contributing to encroachment,
[00:30:34.080]prevent the problem from growing?
[00:30:38.640]And then, do projects work together?
[00:30:40.020]So if we're doing a tree removal here,
[00:30:44.640]are there projects down the line
[00:30:47.220]that are gonna support that work,
[00:30:48.930]manage the re-encroachment process,
[00:30:50.910]and then build on that project
[00:30:52.380]to add synergy to how we manage a problem
[00:30:57.180]and kind of support growing grasslands?
[00:31:00.667]And so to that point,
[00:31:02.670]I wanna share this.
[00:31:05.850]What's kind of emerged as a mantra
[00:31:07.440]for how we manage plant invasions like cheatgrass
[00:31:11.280]in the Western United States
[00:31:12.810]and woody encroachment in the Plains is this mantra,
[00:31:15.397]"Defend the core, grow the core."
[00:31:18.630]And so instead of managing randomly across the landscape
[00:31:21.870]or a property or targeting the most infested areas
[00:31:25.950]where we talk about it as emergency care,
[00:31:29.850]what this approach does is it anchors
[00:31:32.100]to our most intact grasslands
[00:31:34.380]and then focuses management on the boundaries
[00:31:36.570]to grow those areas over time.
[00:31:39.720]What this does is it creates an approach
[00:31:41.550]to conserving our grasslands that's scalable.
[00:31:45.600]Woody encroachment has been so successful
[00:31:49.140]in its own terms because it's contagious.
[00:31:53.040]We have a seed source that spreads,
[00:31:54.600]that leads to new seed sources that spread,
[00:31:56.790]and the problem can spread across the landscape.
[00:32:00.480]What this approach does
[00:32:01.470]to conservation is it helps make conservation contagious.
[00:32:05.640]If we can take a core
[00:32:08.490]and expand on it and grow it over time,
[00:32:10.830]connected among properties,
[00:32:12.810]that gives us a way to make conservation contagious
[00:32:16.800]and scale up grasslands.
[00:32:21.870]I wanted to give one example of this.
[00:32:24.480]So this is the Nebraska National Forest at Halsey.
[00:32:28.830]And in about I'd say 2017,
[00:32:33.990]they adopted a strategy,
[00:32:35.910]a new strategy for managing encroachment on their property.
[00:32:39.840]And so in black,
[00:32:41.160]we have the hand-planted forest.
[00:32:44.640]In dark red here,
[00:32:45.960]we have the surrounding grassland
[00:32:47.850]that in 2010 was encroached.
[00:32:49.890]It had mature, seed-producing trees throughout it.
[00:32:54.450]They had experimented with some,
[00:32:56.850]I'll say traditional management approaches
[00:32:59.520]and had really bad outcomes.
[00:33:01.920]And so they sat down and came up
[00:33:03.750]with a more targeted and strategic approach
[00:33:05.850]to managing encroachment on the property,
[00:33:08.220]which is about 100,000 acres.
[00:33:12.810]By 2020, they've established multiple cores.
[00:33:17.220]So what they're doing here is they're coming in
[00:33:19.680]with mechanical equipment.
[00:33:21.150]They're removing every single tree in these units.
[00:33:25.200]Within the next six years,
[00:33:26.940]they're implementing a prescribed fire.
[00:33:28.740]What that does is it consumes the seedlings
[00:33:33.810]that the mechanical treatments missed.
[00:33:36.360]And then, the seed that's left over,
[00:33:38.610]if they let that sit for a few years,
[00:33:41.430]seeds are not very vulnerable
[00:33:42.900]to most of our management techniques.
[00:33:44.730]Fire's actually the only thing that can kill a seed.
[00:33:47.970]But by letting it sit for a few years,
[00:33:50.010]those seeds can germinate, become a seedling,
[00:33:52.800]which is much more vulnerable to that fire treatment
[00:33:55.110]when it passes through.
[00:33:58.140]So they're accounting for re-encroachment.
[00:34:00.750]And then, over time,
[00:34:02.670]they're repeating this approach and growing it
[00:34:04.590]in adjacent units.
[00:34:06.960]Today, they've actually expanded this green area,
[00:34:09.660]I refer to it as the core,
[00:34:11.850]onto adjacent private lands.
[00:34:15.720]And then, one more thing I wanted to point out too is
[00:34:19.120]this dispersal buffer or this band around all our cores.
[00:34:25.980]We put that in there to account for seed dispersal
[00:34:30.570]and recruitment that happens at the edge,
[00:34:32.460]so where you have the intact area
[00:34:33.840]that's next to the seed sources.
[00:34:36.480]Their plan to manage that orange area,
[00:34:39.810]that orange strip that's 200 yards,
[00:34:43.770]where 95% of dispersal occurs,
[00:34:46.440]is to use a fire within every 10 years
[00:34:49.920]to come through and burn the entire unit
[00:34:52.470]to prevent those units from being kinda collapsed in
[00:34:55.590]from the outside in.
[00:34:57.840]So their future vision is to continue growing it
[00:35:03.390]throughout the western side of the property,
[00:35:06.420]eventually coming back to the east and being able
[00:35:10.080]to maintain that too.
[00:35:13.860]That's all I have for my presentation.
[00:35:16.380]Thanks, everyone, for listening.
[00:35:18.619](audience applauding)
[00:35:22.350]Thank you, Dillon.
[00:35:25.200]Josie, we've got Nancy over here with a question.
[00:35:27.900]We'll bring a mic over here to you, Nancy, real quick.
[00:35:32.640]We got a couple minutes for questions.
[00:35:39.747](Nancy asking indistinctly)
[00:35:54.720]Yes, it reduces.
[00:35:57.060]Yes, we've actually seen higher rates
[00:35:59.610]of seedling recruitment after a drought.
[00:36:05.550]So yes, that has been observed.
[00:36:08.610]And what we're seeing is oftentimes,
[00:36:13.080]we see more bare ground during a drought,
[00:36:15.180]and that creates more sites that are more ideal
[00:36:18.360]for seedling germination.
[00:36:29.430]I've got a question
[00:36:30.263]that goes a little bit the last thing you talked
[00:36:32.054]about fire (indistinct).
[00:36:35.192]If you have a grassland that,
[00:36:36.900]we'll say they're all smaller trees,
[00:36:38.490]maybe nothing taller than three foot,
[00:36:40.920]if you were to remove them mechanically versus burning,
[00:36:45.360]would there be a difference
[00:36:47.430]in how the re-encroachment happens, do you think?
[00:36:51.930]So yeah.
[00:36:53.820]The things to consider are
[00:36:56.190]that fire is gonna remove trees that are this tall.
[00:37:01.950]Mechanically, you're not gonna remove those.
[00:37:04.290]So one fire treatment might remove 100%, 95% of the trees.
[00:37:11.700]The mechanical removal treatment,
[00:37:14.160]you're only gonna remove the ones you can detect,
[00:37:16.590]which might not be very,
[00:37:19.080]it might be a small percentage
[00:37:20.520]of the total population of trees.
[00:37:23.070]If you still have the seed source nearby
[00:37:25.290]and so you have that continual incoming seeds,
[00:37:30.720]that's another factor to consider
[00:37:32.130]because you're gonna need much more treatments mechanically.
[00:37:38.370]And then, fire,
[00:37:39.270]you're also gonna need a rotation that prevents those trees
[00:37:43.260]from becoming seed-producing trees.
[00:37:45.630]Does that answer your question?
[00:37:48.720]One final question up here in the front.
[00:37:52.320]So it seems like this is gonna be
[00:37:56.100]a fight that we'll be fighting for the foreseeable future.
[00:38:00.270]Is there a permanent solution yet
[00:38:02.340]or is this gonna be something
[00:38:03.360]that we'll have to continue to fight and use, you know,
[00:38:07.440]flame, mechanical means?
[00:38:10.050]Or is this ever going to end is what I'm asking
[00:38:14.160]or are we in for the long haul?
[00:38:15.810]We're in for the long haul.
[00:38:17.310]There's no examples anywhere of the problem being reversed
[00:38:23.760]at large scales once it's started.
[00:38:28.080]That being said,
[00:38:28.913]at a property scale or if we can eliminate exposure
[00:38:34.140]to the problem,
[00:38:38.550]it reduces the amount of work
[00:38:41.190]that needs to go in repetitively
[00:38:43.050]to keep an area in a grassland state.
[00:38:45.210]And so that's this emphasis on managing exposure is
[00:38:49.230]we can reduce future needs for management.
[00:38:52.620]But that does not mean we'll be able to walk away
[00:38:56.820]and wipe our hands of the issue.
[00:39:01.260]Wonderful.
[00:39:02.370]If we do have further questions,
[00:39:04.170]Dillon will be around to answer any after
[00:39:08.010]during the lunch break.
[00:39:09.180]Feel free to catch him after.
[00:39:11.550]So again, thank you, Dillon,
[00:39:12.810]and we'll transition to our next speaker.

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Reducing Eastern Redcedar Encroachment in Grasslands

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