Wildfire Recovery at The Niobrara Valley Preserve – Asking The Big Questions

Most of you are familiar with the wildfire that affected our Niobrara Valley Preserve this summer.  Well, we’re still trying to regain our footing after that event.  A great deal of time and money has already been spent on rebuilding and redesigning infrastructure (especially fences), but there’s still much to do.  In addition, the staff of the Preserve, along with a few of us from around the state, has taken this opportunity to do some deep thinking about what the Preserve can be in the future.  It’s an incredible place, and we want to be sure it lives up to its potential.  I’ll share more about that process as the picture becomes more clear.

The

The Niobrara River continues to flow through the Preserve, but much of the landscape looks pretty different since the fire.  Open grassy slopes such as this one will recover quickly, but more wooded areas will come back much more slowly.

In the meantime, we’re also trying to learn what we can from the 2012 wildfire so that we and others can be more prepared the next time something like this happens.  I’ve been asked to help organize this effort, which is an intriguing task for me since most of our questions are about woodlands – not exactly my area of expertise.  Fortunately, I’ve had some great advice from others, particularly Dr. Dave Wedin at the University of Nebraska, who is also generously helping us line up researchers and funding.  Other advice has come from a wide spectrum of foresters, ecologists, and others, and I appreciate it all.

I was up at the Preserve last week for another bison roundup (the west herd this time) and had some time to poke around in the hills and think about our current list of research ideas.  I think we’re honing in on a few important research directions, but we still have some thinking to do about how to ask and answer the right questions.  Since we’re at a good point to get feedback from others, I thought I’d lay out some of what we’re thinking and see if any of you have suggestions for us to consider.  If nothing else, those of you who are familiar with the Preserve, and concerned about the impacts of the fire, can get an update on the situation and a feel for where we’re going next.

Yucca are starting to regrow across the burned portions of the Preserve.  Many show signs of being eaten - there's not much else green out there!

Yucca are starting to regrow across the burned portions of the Preserve. Many show signs of being browsed by deer and other wildlife – there’s not much else green out there!

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Wild rose is another of the plants regrowing in the burned areas.  These woody plants, perennial grasses, and sedges make up the bulk of the surviving plants.

Wild rose is another of the plants regrowing in the burned areas. These and other perennials, including grasses, sedges, and wildflowers, are most abundant in open areas without dense stands of trees.

Our primary research objective is to learn lessons that will help us and others adapt our pre- and post-wildfire management in the future.  It would certainly be interesting to simply document the way in which plant and animal communities recover from the fire, but that has been done elsewhere.  With very limited resources, we’ll spend a little effort documenting how the Niobrara Valley Preserve recovers from the fire (including the use of time-lapse and other photography) but we want to focus most of our effort on learning things that we and others can actually use down the road.

Impacts of Tree Density

The first thing we want to know is how the density of eastern red cedar and ponderosa pine trees affected the way the fire burned  and (more importantly) the way the areas beneath the trees will recover.  In addition to the perennial plants that survived the fire, much of the future plant community in our former pine woodland will depend upon the seed bank (the collection of seeds sitting in the soil, ready to germinate when given the chance).  Unfortunately, areas under dense tree stands are also the most vulnerable to soil erosion.  Especially on steep slopes, wind and water erosion can quickly remove both seed and soil, leaving very little to support plant community recovery.  Since there were few herbaceous (non-woody) plants under dense tree stands, there is little to hold the soil (and the precious seeds in it) from washing and blowing away.  If seeds and soil go, it’s going to be a very long time before anything grows in those places.

Soil erosion will probably be an issue on steep slopes and under formerly dense stands of trees.

Soil erosion will probably be an issue on steep slopes and under formerly dense stands of trees.

We hope to correlate the amount of soil erosion with tree density and slope, and see how those factors affect plant community recovery.  Ideally, we can combine our data with what others have learned elsewhere and develop recommendations for future management.  We want to know how densely can we allow trees to grow before the site becomes vulnerable to severe erosion in the aftermath of a potential wildfire.  Hopefully, that information can help managers decide how to prioritize tree thinning operations.

Much of the erosion that's occurred so far appears to be wind erosion.  A 70 mph wind storm got sand moving in some areas.

Much of the erosion that’s occurred so far appears to be wind erosion. A 70 mph wind storm really got sand moving in some areas.

On a related topic, we want to see how cedar and pine density affected the survival of bur oak trees.  It’s clear that we’re going to have varying degrees of recovery among the oaks growing on the lower slopes of our pine woodlands.  Some of the oaks have already re-sprouted from the base, but others haven’t.  Those others are either completely dead or waiting to resume growth from the tips of their branches next year.  What could we have done as land managers to prevent oak mortality by thinning the cedars and pines near those oaks?

Many of the bur oaks in the burned area are re-sprouting from the base.

This oak is re-sprouting from the base – it’s still alive, but has to start it’s growth over from the ground.

Aiding Recovery

We also have questions about how best to manage the recovery of burned sites.  Some people are advocating seeding burned areas to speed up the establishment of herbaceous and/or woody plants.  There are numerous concerns about this, including what kind of seed would be used and whether or not it would actually make any difference.  We certainly want to avoid introducing plant species that could cause more problems than they solve, but the bigger question is whether or not seeding will make a difference when the most problematic areas are those where soil erosion rates are high.  Putting seed in those erodible areas probably won’t do much good. However, while we and most of our neighbors will probably not be doing large-scale seeding, we might consider a few small-scale trials to test the idea.  We could broadcast seeds in a few trial plots and see if the plant community establishes differently within those plots than elsewhere.

Aside from any seeding efforts, the recovery of ponderosa pines in large swaths of burned woodland is likely going to be dependent upon seed coming from unburned areas.  Because of the size of burned areas, that could take a very long time.  Is it worth trying to speed up that recovery by planting small patches of ponderosa pines in various locations, with the idea that as they mature, those trees would be seed sources for nearby establishment – thus speeding overall woodland recovery?

A few mature ponderosa pines may have survived along the very top of the ridge north of the river.  If so, new pines may be able to spread from these pockets of survivors.

A few mature ponderosa pines may have survived along the very top of the ridge north of the river. If so, new pines may be able to spread from these pockets of survivors.

The answer to that question is related to another big question.  How do we manage these burned woodlands over the next couple of decades – especially in terms of prescribed fire?  At first glance, it might seem that we’ve had enough fire to last quite a while.  On the other hand, prescribed fire might be pretty important to help prevent cedars from coming right back in, and to give us some control over the overall recovery trajectory.  If we do employ prescribed fire, that’s going to impact where pines will be able to survive – including any we plant and those that come back on their own.

Very few pine cones can be found away from the very top of the ridge.  A few isolated exceptions like this might produce a few trees, but future prescribed fires may not allow many of those to mature.

Not many pine cones can be found away from the very top of the ridge. A few isolated exceptions like this might produce a few trees, but future prescribed fires may not allow many of those to mature.

Grassland recovery from the wildfire comes with questions too.  We have choices to make about whether to graze some of those drought and fire-stricken prairies immediately or to rest them for several months or longer first.  In our bison pastures, bison are never removed, so grazing resumed immediately after the fire.  We could build some exclosures to look at how immediate grazing impacts grassland production and species diversity.  In addition, we can manage our cattle pastures in several different ways and measure the results.  What we learn could help us and others make informed decisions after future wildfires.

The last big question we’re struggling with has to do with invasive species, especially in burned woodlands.  I’m not sure yet how to formulate a research question on this topic because we don’t yet know what kinds of invasives we’ll be dealing with.  Some plant species will be much quicker to colonize burned woodlands than others, but whether they will include truly invasive species – and which ones they might be – will be unknown until it happens.  We may just have to be ready to react as quickly as possible when we see what happens, and try to learn from our experience as we attempt to contain any invasions that occur.

We don't yet know what will be growing here in the coming years, but something will - and it will continue to be a beautiful and ecologically important place.

We don’t yet know what will be growing here in the coming years, but something will – and it will continue to be a beautiful and ecologically important place.

There are plenty of questions we could ask about the impacts of this wildfire.  We’re hoping to focus on those that might be the most useful to us and others when dealing with future wildfires.  We have our draft list, but would be happy to hear from anyone with suggestions of other questions we should consider or how we should prioritize among the questions we have.  Thanks for your help and support!

I'm smiling here, but as a prairie ecologist, I'm pretty far out of my element trying to help restore pine woodland.

I’m smiling here, but as a prairie ecologist, I’m pretty far out of my element trying to help restore pine woodland.

If you’re interested in contributing toward the recovery of the Niobrara Valley Preserve, please click here.

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About Chris Helzer

Chris Helzer is an ecologist and Eastern Nebraska Program Director for The Nature Conservancy. He supervises the management and restoration of approximately 4,000 acres of land in central and eastern Nebraska - primarily along the central Platte River. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press.
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22 Responses to Wildfire Recovery at The Niobrara Valley Preserve – Asking The Big Questions

  1. David Burg says:

    Thanks for sharing your thoughts on the Niobrara burn. In terms of issues like planting trees or spreading seeds, or even erosion control, my instinct is “what is wrong with what the fire did? Why not let things take their course, a lot could be learned from that.” For example, there are species (thinking of breeding turtles, but there are many more) that like and need some bare ground. Is there some fixed idea of how many trees, or amount of woodland, (or grassland or shrubland, for that matter), that there should be on the property? If, on a landscape scale any particular community is a rare habitat that harbors rare species one could more sympathetically view manipulations. But these sorts of decisions are tricky. If the goal is merely to recapture what was the historic vegetation pattern of this property, what point of post glacial history should be used as the goal?

    • Chris Helzer says:

      David, good points and questions. I don’t have any preconceived idea of what the site should look like. I think we want the Preserve to add diversity and resilience to the landscape around it, and we want to provide for the viability of some of the unique and rare species and communities that occupy the Preserve. That broad objective allows for a lot of variation in the way we allow/manage the recovery of the site. I don’t have the answers yet, but I think we’ll frame them within that kind of broad context. Picking a point in time for a reference is definitely not the way to go. We need to look forward.

      • David Burg says:

        Yes, I struggle with this issue…how to balance history and the future. I do not hold with those who say “all novel ecosystems are fine, get used to it”. But there is no going exactly back to a non existent golden age. Not possible, even if we “rewild” by cloning the ice age megafauna. Can’t find the reference, but I think it was Dan Simberloff who made a similar point in a paper on History vs Process in ecosystems.

      • Jeff Evander says:

        Chris This is really neat work going on!! Have you checked out a land use/fire intervel history your ponderosa pine areas on the preserve? Also use Pine Ridge and the Rose bud areas in South Dakotah as existing templates for the Niobrara preserve. What I’m getting at is the pine density/postion on the terrain and grazing rate/history as well as burn history of the Pine ridge/Rosebud region. Interestingly the poderosa pine seems to be on ridgetops than on slopes. I noticed in you’r posts and photos that the ponderosa pines suvived mostly on ridgetops. Has any age/fires scar studies been done?
        Chris, I’ve some study footage from Mongolia in regards to fire intervel in forest steppe[prairie] there, but instead of poderosa pine and burr oak it’s scotch pine/siberian larch. However in Mongolia the burn history intact to the present—-no smokey the bear phase there. The scotch pine fire scars on live trees go back 200 years!!!!. The take home of this is big enough gap in fire history to allow the ponderosa to fill in too thick and then fry duff and all!. The same thing happens to prairie too I’ve seen it happen here in Minnesota. Gotta study area here that I’ve been working on since 1970.
        It’s 2 am and I could on and on so I better sign off Jeff Evander

        • Chris Helzer says:

          Thanks Jeff,

          Lots to respond to…! Yes, we’re definitely looking at the Pine Ridge/Rosebud areas as models of what can happen at our site. Yes, there have been some fire scar studies done (Tom Bragg) and he’s likely going to do some more now, taking advantage of the burned, but still standing trees.

          Hopefully, we can get this area (woodland and prairie alike) back into a fire regime that is regular enough to keep cedars at bay, and the density of other trees to a manageable level.

  2. This blog is a wonderful way of documenting and collecting your thoughts and ideas as well as providing information and data others can use going forward. A digital lab notebook with photos, not sketches. Thanks for taking the time to provide this information.

  3. Duke Engel says:

    Hi Chris, Three times my group of volunteers has arrived to cut down cedars off the north mountain. We planned to come again in October and I argued that in spite of the fire there were plenty of cedars left on the Preserve but Tracey said that with all the pressing priorities after the fire, the timing was terrible. I want to continue to build momentum with our group but could use guidance from you and the staff at the Preserve how we could best serve.

  4. Crystal says:

    Thinking about the need for erosion control, a couple ideas popped in my head: you could cut some of the dead trees and leave them parallel to the slopes creating lots of little natural terraces to slow water and catch soil. As the tree begins to break down it adds organic matter and nutrients to help the new plants and trees. Leaving a few standing and moderate the winds to slow wind erosion.

    Another idea could be if you feed hay to any of the bison, do it on areas that need soil cover they will trample in some wasted hay and add lots of fertilizer through manure. They hay locations could be moved with each feeding to spread around some natural ground cover.

    I agree that the fire was a natural process, maybe long overdue which is what made it more intense. Good luck finding a good balance of managed fire, animals, and human impact for your beautiful location!

  5. Angela Anderson says:

    Hi Chris,
    I really enjoy your blog. I stopped at the Niobrara Preserve in mid September on my way home visiting my daughter at the Crescent Lake National Wildlife Preserve.Although the fire did a lot of damage to the pine forest, must have been a very hot fire, the open areas were already coming alive again. It will take some collaboration to come up a strategy for future management.
    Angela Anderson

  6. Michael Scullin says:

    I see anywhere from 5-10 cm of soil gone in some of your pictures. Have you thought to install erosion pins on various slopes? We have used them and the data are not only useful but precise. We used pole barn spikes on our transects so that 1 cm was exposed initially. We measured the mm exposed in the spring and at the end of summer. Quite by chance one of our transects was burned so we got to measure the before and after. We had nothing as dramatic (at that site) as you show but it was good for us to have quantification over a three year period.

  7. Patrick Swanson says:

    A couple comments…I think we will all be surprised at just how fast the understory beneath the cedars and pines will recover after a couple growing seasons if we have some decent rains. Remember what the pundits said about the recovery after the Mt St. Helens eruption and the Yellowstone fires. In my experience clearing stands of large cedars with fairly little undergrowth in the Loess Hills, the response has been quite dramatic in a period of two or three growing seasons. I have noticed that the first couple of seasons are dominated by annuals, short lived perennials, and big bluestem and Indian grass, presumably taking advantage of the high organic content of the accumulated duff. Gradually, it has been replaced by shorter grasses and longer lived perennials. I’ve been fairly lucky avoiding nasty invasives, although I have targeted bull thistle. I have taken the approach to lay down cedar logs parallel to the slope, particularly to reduce gully formation on old cow paths. It does help, but I have not seen as much erosion as I might have initially expected. The land is definitely resilient, and most of these areas probably have a deep seed bank, and “memory” of being prairie woodlands. Bottom line, I don’t think I would advocate overseeding, unless there was heavy erosion. In that case, one might stabilize the slopes with logs, and maybe cover with prairie hay, keep the cattle off for a growing season, and see what happens. Your hand might be forced by invasives, which may require spot treatment or targeted grazing, but as you suggested, you will probably need to wait to see what you’re dealing with. One final comment…you might consider cattle exclosure to examine recovery/establishment of lichen and cryptogamic soil crusts, particularly if it continues to remain dry. Sorry for the long post. It will be fascinating to watch and see how it recovers, and what, if any, intervention is required to help this process.

    • Chris Helzer says:

      Thanks Patrick – good comments and ideas. I agree with your optimism, though I think the drier climate, steeper slopes, sandier soils, and rockier slopes will make the pine woodlands on the Niobrara difficult to predict from the Loess Hills – and even Mount St. Helens. Probably the Pine Ridge is a more analogous situation, and I need to spend some time out there learning about that recovery. My memory of hiking through some of the 1988/89 burned areas 5-6 years later was that herbaceous cover looked pretty good.

      In any case, something will grow there, it’s just a matter of what and when. Should be fun to watch.

  8. Great take on fire severity and mitigation efforts.

    It would be interesting to compare the results here with the big fires in the Wichita Mountains NWR. I understand they had what amounted to a high severity fire in their grasslands and woodlands, including so-called “stand replacement” in grasslands (grass replaced entirely by forbs.) Did you do any composite burn index plots or attempt to map severity (dNBR or otherwise)?

    Have you noticed an increase in cheatgrass, by any chance?

    • Chris Helzer says:

      Daniel, sounds like an interesting comparison to be sure. We didn’t do any severity mapping ourselves – not sure if Park Service or others did. I’d be surprised if we see any stand replacement in grasslands – we’ve had summer prescribed fires before that recovered as we’d expect. This one might actually have less impact on grassland vegetation because the drought had forced many grasses into early dormancy prior to the fire. I’m sure we’ll see lots of cheatgrass, but it’s not a species that is usually considered a major threat in the area because there is sufficient annual moisture to prevent it from becoming a long-term invasive (it’s more of a temporary space filler in most cases). Further west, it can be a much more severe problem.

  9. James McGee says:

    Chris, I have been mulling over your questions for a few days. The “do nothing” option still ways heavily on my mind. The thought of your dilemma makes me think of Henry Cowle’s studies at the Indiana Dunes. In that ecosystem, efforts to stabilize slopes would likely be in vain since the lake would continue to create waves and the sand would continue to blow. Your situation is different. An event of this severity is a rare occurrence in the Niobara River valley. Hopefully, this sort of disturbance will continue to be a rare.

    My next thought is Fort Robinson. The pines that burned in the fire of 1989 have never returned. Might the pines cover the hills again? Yes, however in 23 years they have not even begun to spread back into the areas they had previously occupied. I then think about the “Pinery” at Illinois Beach State Park that was plant by sowing seed from horse back a century ago. The pines at Illinois Beach State Park are all introduced species. If they could establish non-native pines so easily at Illinois Beach State Park then I expect you could do the same with the native Ponderosa at the Niobara River valley.

    So the question becomes … what legacy do you wish to leave? If you do nothing, the hills will likely remain in grassland for many decades or centuries. If you intervene with planting or seeding, these hills may begin to look as they did before the fire by the time you leave the job of stewardship to the next generation. The question is less one of what you should do, and more the question of what you wish to leave for Nebraska’s children.

    James

  10. James C. Trager says:

    Lots of good thoughts in these posts. I lean, from a position of both hopefulness and a little experience, toward the “Do the least necessary, watch for invasives, nurture the natives” approach. James McGee’s suggestion that broadcasting ponderosa pine seed could help speed the recovery of that species seems well worth considering.
    A question for Patrick Swanson: What is this memory you speak of? Sounds sort of mystical to me. The memory is the seed bank, and whatever other viable biological remnants, remaining after the fire. And like all memory, it can be partial, and even distorted.

    • Patrick Swanson says:

      James, I can’t claim credit for this terminology, and agree that on the surface it would seem somewhat mystical, but it derives from observations of restorationists that areas that had been brushy tend to have a continuing problem with brush, despite attempts at overseeding etc, and conversely areas that were good grasslands tend to recover more quickly. I see this on my own prairie and oak woodlands. For example I have bur oaks saplings sprouting in one particular location, and not another nearby site, and some areas after mechanical shearing and grinding of cedars, some areas returned quickly to grassland, and others quickly to more cedars and brush. I’m sure it has to due partly to seed bank, but I don’t think that is the whole story. I think the microbioata also plays a key role in determining which species have a competitive advantage in recovery/ restoration. This would be the “memory” I speak of. And I agree, much like memory, it can be lost or partial, depending on the history of the site. And much like memory, we don’t fully understand how it works.

  11. Joe says:

    Although the effect of fire on soil nutrients has been looked at before, it would be interesting to track nutrient uptake over time using foliar analysis of the remaining Ponderosa and the stump sprouting Burr Oaks. It may offer some clues as to whats going on in the dirt and how the site is recovering. Enjoying the posts!

  12. prairienut says:

    Maybe you can go the route of resilience planning. If you can identify a suite of species that are most likely to be successful in light of predicted climate conditions, perhaps those are the ones that should be promoted.

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