Restoring Cottonwoods to the Missouri River – Part 1

Last week, I had an experience that doesn’t come often to a prairie ecologist.  I participated in a tree planting project.  Well ok, we weren’t exactly planting trees, but we were laying the groundwork.

Collecting cuttings from cottonwood trees for a Missouri River restoration project. This is a panoramic made from two photos stitched together. Click on the photo to see a larger version.

It’s kind of a long story.

Over the last few years, The Nature Conservancy has been working with the Natural Resources Conservation Service (NRCS) on wetland restoration projects along the Missouri River in eastern Nebraska.  Tyler Janke, a Conservancy employee, has – among other things – helped design, implement, and evaluate restoration projects implemented through the Wetland Restoration Program (WRP).  One of Tyler’s major contributions has been to facilitate the use of high-diversity seed mixes at a number of sites.  I’ll write more about that effort another time.

As the number of WRP projects has grown along the Missouri river, one important lesson has been learned by the Conservancy, the NRCS, and other partners.  Although the traditional model of wetland restoration in Nebraska has been to convert wet crop fields to wetlands dominated by grasses, sedges, and other herbaceous plants, that model has turned out to be inappropriate in many places.  Why?  Because most herbaceous plants can not survive the kind of frequent and severe flooding that occurs in some portions of the Missouri River floodplain.

So what to do?  Trees.  Tyler and others have modeled the floodplain and identified areas where frequent flooding and sediment deposition are likely, and those areas are being proposed as places where cottonwood woodlands should be.  Cottonwood woodland has disappeared from much of its historic range along the Missouri River, and what remains is largely stands of old trees.  Over time, the lack of young and middle-aged stands of cottonwoods will lead to a drastic change in habitat for many species in the Missouri River valley.

No problem, then.  We need more cottonwood woodlands, we can’t get grass to survive in many places anyway – let’s just plant those areas to cottonwoods, which are better at surviving flooding and sediment deposition.  Well, as it turns out, there are quite a few questions about how best to do that, and what the cost effectiveness of various methods are.  That’s where Tyler comes in again.  Through a partnership between the Nebraska Forest Service, the Arbor Day Foundation, and The Nature Conservancy, Tyler is leading an effort to create experiment and demonstration sites for Missouri River cottonwood restoration.  Funding for the project comes from the U.S. Forest Service, the Arbor Day Foundation, and State Wildlife Grant funding through Nebraska’s Natural Legacy Project.

I’ll summarize the entire project design in a future post, but suffice it to say that over the next three years, we plan to establish 300 acres of new cottonwood woodlands on WRP lands.  We’ll experiment with a variety of methods, including the planting of cottonwood cuttings and seedlings.  And that - finally – brings us back to what I was doing last week.

For the first year of the project, Tyler needs to come up with 30,000 cottonwood cuttings.  This spring, those cuttings will be put in the ground, and hopefully most will grow into new cottonwood trees.  Should be great.  First, however, we need to find 30,000 cottonwood cuttings!

It turns out it’s not difficult to get cuttings that can grow into trees.  You just need to cut 8-12″ sections from stems that grew during the previous growing season.  When those stems are put in the ground, the buds on the stems will facilitate the process of transforming them into new trees.  In order to get 30,000 cuttings, Tyler (with the help of others) has organized several volunteer workdays this month.  Last week, I joined other staff from The Nature Conservancy and the Arbor Day Foundation in a joint effort to collect as many cuttings as we could on a wet foggy winter morning.  The following photos are from that day.

It was a muddy ride out to collect cottonwood cuttings.

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Tyler found a site where a large number of young cottonwoods had grown where they weren't wanted. Tyler cut those trees down so our crews could come along and easily harvest the active growing tips of their branches.

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Matt Harris of the Arbor Day Foundation harvesting cottonwood cuttings.

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Cuttings were collected in buckets and hauled to a central collection point.

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A batch of cottonwood cuttings, counted, banded, and ready to store until they are planted in April. This tub contains several thousand potential new trees. The total count for the day's harvest was 12,500 cuttings.

The cuttings we harvested will be planted later this spring, and their success will be compared to the other methods of cottonwood establishment Tyler is testing.  The experience of others, and some pilot work we’ve done, shows that cuttings are a pretty dependable way to establish trees – so hopefully the majority of those 30,000 cuttings will turn into new trees.

Since much of my career has been spent removing trees (including a lot of cottonwoods) from prairies, this is a new experience for me.  I completely understand and agree with the logic and strategy of the project.  It’s just a little bit difficult to adjust my mindset.  So far, I’m doing fine.  We’ll see how I feel when we actually put the trees in the ground…

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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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13 Responses to Restoring Cottonwoods to the Missouri River – Part 1

  1. James C. Trager says:

    I can just hear the director of the site where I work comment, with a sneer, “Cottonwoods! What are they doing that for?” But I get it. They are important habitat for a lot of critters in plains and western landscapes otherwise mostly lacking large trees.
    The surprising thing is they don’t restore themselves to the places they’re going, and that you’re removing them from places they’re “not supposed to be” to get the cuttings.

    • Jeff says:

      We have had good success restoring cottonwood along the Minnesota River floodplain with natural regeneration. Essentially a cropfield is tilled in fall to create a bare seed bed and the seed comes in on its own in the spring and summer as mature cottonwoods go to seed. You also get a lot of willow with this method, but the cottonwood ultimately outcompetes them. There can be issues with noxious weeds (especially Canada thistle in our area) but bad infestations in young restorations can be treated with chemicals without hurting the cottonwood

  2. Martha says:

    Why not “cottonless” cottonwood trees aka poplars? They add fewer alergens and do just as good a job.

    • Two words, Martha: Not native.

    • Chris Helzer says:

      Martha – James’ comment is exactly the same as mine. We’re trying to enhance the whole ecological system, which includes the native trees and all of the tiny (and micro) organisms that depend upon those particular species. I’d be shocked if there weren’t some kind of little species that relied specifically on cottonwood seeds for a part of their life cycle.

  3. Keith Long says:

    Hey Chris – is this area open to cattle grazing? Cows love young cottonwood trees, which may be why they aren’t many young trees there. When I worked in eastern New Mexico, we excluded cattle from grazing the riparian areas during the growing season and saw a huge increase in cottonwood saplings. The cattle did graze it during the dormant season, but the young trees had a chance to establish first, and they may not have been as desirable in the winter.

    • Chris Helzer says:

      Hi Keith,

      I agree with you about grazing on cottonwoods – in fact, I’ve seen partners use grazing as way to suppress cottonwoods where they weren’t wanted. In these sites, though, cottonwoods aren’t being held back by grazing (in the vast majority of cases) but by large scale row crop agriculture that has replaced natural communities in most of the floodplain and by an altered flood regime that doesn’t create the correct conditions for cottonwood germination at the right times and places.

  4. I seen and heard about land managers along the Mississippi planting only oak or mixes of oak and cottonwood (they are very ‘mast’ focused for wildlife). They then keep the understory mowed. While I recognize the difficulty of managing invasive species in a floodplain and the limited selection of species that survive or thrive in flood-prone areas, I am saddened that the habitat provided by understory flora are unavailable.
    That said, I am curious about how these WRP lands will be managed. Will there be any effort to develop an understory? Are there plans to add other species to these woodlands? I hope these sites will not be managed as a monoculture – with single-aged stands of a relatively short-lived species like cottonwood, this may just be asking for trouble down the road. We really need to strive for diversity in both our prairie and our woodland habitats.

    • While I’m not involved in the project Chris and Tyler are working on, I’ve been involved in other large-scale restorations of woody plant communities and perhaps can provide some insight to your concerns Danelle. For one thing, my sense from Chris’ post is that this is new territory they’re striking out on – restoring Missouri River floodplain forests, so their techniques aren’t well developed, including the level of diversity in propagation material they can work with. Chris and Tyler both have extensive experience with high diversity restorations of herbaceous communities and I’m sure as they gain experience with Missouri River floodplain forest restorations, the diversity of their propagation materials will increase. But another interesting consideration is that a floodplain forest restoration strategy that focuses on cottonwood (or willow, or cottonwood and willow) for a Great Plains river may be entirely valid. These species are supremely adapted to capitalize on the highly dynamic nature of Great Plains rivers and streams where frequent scouring flows provide a seedbed where they are often the only tree species to colonize a site, resulting in essentially monotypic stands that only diversify through slower successional processes.

    • Chris Helzer says:

      Danelle, you and I think alike on this.

      As promised, I will lay out the larger project design in a future post, but one aspect that I’m insisting upon is that we’re going to be experimenting with the idea of creating an herbaceous understory. The question is, should we create that understory community simultaneous with cottonwood establishment or wait until the trees establish and then try to put the herbaceous community in later? We’re going to try both ways. Because there aren’t many examples of cottonwood communities in Nebraska where there is a strong and diverse understory community, we’ve been doing a fair bit of research into what those herbaceous species should be, and we’ll be seed harvesting a mixture to fit what we’ve found in the literature and on the few reference sites we have.

      I’m with you – most woodland restoration projects that start from bare ground tend to focus solely on trees with the idea that the herbaceous community will take care of itself or that its unimportant. The result is often a pretty sterile community and/or one that becomes a few dominated by aggressive or invasive herbaceous plant species. We’ll see if we can come up with alternatives to that!

  5. Pingback: Restoring Cottonwoods to the Missouri River (Part 2) | The Prairie Ecologist

  6. Manidoonateshiingkwe / Phylmarie Fëss says:

    Like you, Indigenous peoples understand the import of symbiotic balance in environments, from below ground level, through to branched canopies. Your continued encouraging discussions together and of one another and physical actions will be fruitful. Continue.
    There is a saying. “Trees, the elder Brothers and Sisters in creation, call to the wind, – the breath of Mother Earth, and call to the rain, – the blood of Mother Earth. And with such calls, Trees follow another of Creator’s work for them, to balance effect of gifting wind and gifting water upon all life.”
    Across our home, by deforestation, currents of both atmosphere and waterways have been corrupted, with ensuing climatic devastation.
    Reset balance can be done.
    Do continue. Spread the word. Ask for more volunteers.
    Manidoonateshiingkwe / Phylmarie Fëss

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