Gardening

saving the fraser fir, a popular christmas tree, with missouri botanical’s travis hall

ADD THIS TO the “Things I Didn’t Know” file…and by the way, merry Christmas. One of the most popular holiday trees of all, the Fraser fir, is under threat in the wild, even though 50 million-plus of them are grown on tree farms in North Carolina alone. So how can that be?

Travis Hall is supervisor of the Horticulture Division at Missouri Botanical Garden in St. Louis, where a project is under way to save Abies fraseri. He helped me understand what’s up with the decline of wild populations of this iconic holiday tree, and the Garden’s efforts to help save this species and others. (Fraser fir detail photo, above, by Harold Smith via Wikimedia Commons.)

Read along as you listen to the December 27, 2021 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify or Stitcher (and browse my archive of podcasts here).

the threatened fraser fir, with travis hall

 

 

Margaret Roach: Thanks for making time during the holidays to talk with us, Travis. And before we dig into Christmas trees specifically, I said in the introduction that you’re a supervisor in the horticultural division at Missouri Botanical. But I know that’s a somewhat different kind of role than it might be at some other public gardens. You’ve described the work of your team there to me as “conservation horticulture.” So can you kind of explain your focus and how it’s different from thinking about just displays and ornamentality and so forth.

Travis Hall: Absolutely. That is a good place to start. At botanical gardens, we’re uniquely positioned to tackle the rapid biodiversity loss that’s happening in the plant kingdom globally. So we have the capacity to think about our work and the collections that we maintain as real vehicles for the conservation of species.

There’s a few ways that we do that. The components of our living-collections process… I guess, the first and kind of the foundation of our method is to operate a seed bank. We maintain a collection of seeds from a number of different target regions globally. And that is a mass genetic storage of seeds. We conserve hundreds and thousands of different collections from the wild, and that repository of genes can be used for research and conservation projects in the future.

So that’s one of the main components. The other component is the living collection itself. So that is really where we bring our horticultural knowledge to bear on conservation—in growing plants, developing protocols and processes to grow, in many cases, endangered or otherwise rare or threatened species.

So the living collection itself is a display. And we think about aesthetics. We think about design. But we integrate that into the conservation mission.

Margaret: Right. So, with this tree, the Fraser fir, I have to say, I’m embarrassed to say [laughter] that I didn’t even know that it was a native tree. I mean silly me, but really, you know, things like “Christmas trees,” I think a lot of us, we’d say, “Oh, that one looks good. I want that one.” But I don’t think we think botanically about them—I mean, as consumers. So where is it from? Or maybe I should say, where was it from, because I read in the Missouri Botanical blog recently that most of the wild populations have been killed off in the last 50 years. So where was its native range, or where is its native range?

Travis: Yeah, sure; every plant has story. And usually we facilitate that narrative from a very anthropocentric lens. So the Christmas tree is a good example of something that, yeah, we kind of just see it as a Christmas tree. And of course, yeah, there’s millions of Fraser firs growing throughout the East in the mountains.

But yeah, this tree, Abies fraseri is the name of the Fraser fir, commonly known as the Fraser fir. It comes from a number of populations in the Southern part of the Appalachian range. So the there’s a few disjunct populations that occur in southwestern Virginia and western North Carolina, and a few parts of far-east Tennessee, right on the border.

This is a pretty restricted species to these few populations. And as you mentioned, this was part of a much larger population of Fraser fir and red spruce—it commonly occurs with the Fraser. The first spruce forests were vast, and it has declined in such great numbers, up to 90 percent in some of these forests, remaining forests, are lost. [“Ghost” Fraser fir skeletons, above, in photo “View from Clingmans Dome observation tower” by Ben Ramsey, licensed under CC BY-SA 2.0]

Margaret: So that’s like in the Smokies? Was a lot of it in Great Smoky Mountain range, the national park there and so forth? That’s part of where you’re describing, I think.

Travis: Yeah, definitely. Those were some of the most mature populations in the Great Smoky Mountain National Park.

Margaret: I see.

Travis: And yeah, the die-off has occurred over the last 50 years within those remaining populations.

Margaret: So it finds itself now as listed as endangered, on the red list. And so what has been the culprit? I mean, what happened in those 50 years to attack it, so to speak?

Travis: Sure, yeah, the IUCN has listed this as an endangered species, the primary culprit being tiny insect from Europe that was introduced in the 1900s called the Balsam woolly adelgid. This is a little sap-sucking insect. And the Balsam woolly adelgid will interrupt the vascular tissue of mature trees, find its way into little fissures in the bark, and releases some toxins through its saliva into the tree, and will end up stressing the tree and ultimately killing the tree. In some of the populations up to 90, 95 percent of the mature Fraser firs have been wiped out.

Margaret: So you said it’s from elsewhere; it’s invasive. So it doesn’t have any natural predator in the environment that it arrived in, in the Smokies and elsewhere where this tree was/is native. And so it got out of hand.

I mean, I’m a Northeastern resident and years ago and we still have the hemlock woolly adelgid, another tiny, almost looks like a little white cotton underneath the needles of the hemlocks. And I mean, it just transformed our forests that had so much hemlock, almost in no time as you’re describing, relative to all of history I mean. And now hemlocks are a relative rarity. So this is what’s happening there as well with a different species of adelgid.

Travis: Yeah. Unfortunately this same plight has happened with so many different native species. Exotic pests coming in through any number of means. The plants just cannot evolve quickly enough to defend itself.

Margaret: Right.

Travis: It raises an interesting point about evolution and adaptation—that it’s a slow process and it occurs on a genetic level. So certainly ecology is an interdisciplinary field, and we think of community ecology—you know, if all of the Fraser firs are wiped out, what is the trickle-down effect in a forest? But at a genetic level, sort of zoom into the way species adapt, genetics are the cornerstone for adaptation.

And so within a population it’s not just Fraser fir cloned itself. These are all individuals that have a different genetic makeup. And the breadth of that diversity is what can defend against changing climate, against droughts, against diseases and pests. And so when we do the conservation work in the field we try to capture as much of that genetic diversity that occurs.

Margaret: So that would mean seeds [above] from different individual trees. It makes total sense, I mean even for us non-scientists like myself, the best hope for the future that plants have is to sexually reproduce, to set seed (if they’re seed-bearing plants, of course), and to therefore have lots of individuals, each of whom is diverse in the next population and survival of the fittest and so on and so forth. And then the next generations have all this diversity that they bring into the future to face whatever confronts them.

And when, like at those Christmas tree farms, that’s not what’s happening, right? Is that why the Christmas trees aren’t the answer to this, even though there’s tens of millions of them? Because they’re clones, as you just said. They’re not wild populations.

Travis: Yeah, exactly. I don’t know what the commercial industry… I assume that most of the commercially grown trees on a Christmas tree farm are propagated by seed. However, there’s no data that can account for the diversity that occurs on a Christmas tree farm. And so we just don’t know the diversity that the farms are holding. And so it can’t really be used as a tool for conservation.

I think in horticulture at Missouri Botanical Garden, we think about this a lot because what we’re doing is, it’s called “ex situ conservation.” Ex situ, Latin for “off-site.” I guess the converse would in situ, on-site conservation.

Margaret: Right.

Travis: As a botanic garden, we’re positioned to do the critical work of conserving species outside of their native range. So you might think, well, we’re just taking seed out of the wild. How is that conservation? Aren’t we just creating a bottleneck for this species, because it’s not going to thrive and populate itself in a botanical garden.

But we think about this, and a seed bank is a repository of genes so that it can be used for research. It can be ultimately used for reintroduction of that species into the wild. But part of our cultivation techniques are designed to account for the potential genetic bottlenecking that would occur in hybridization, that occurs in cultivation. This is not something I assume Christmas tree farmers are thinking about.

Margaret: Right. It’s a different goal, and it’s a different setting. Yeah, exactly.

Travis: That’s right.

Margaret: In a Christmas tree farm, the interventions they may do—I mean, it’s an agricultural procedure that’s going on. They have protocols; they’re managing the trees. They’re pruning the trees. You know what I mean? There’s so many interventions that are not like a wild population. And the stress factors that the trees are subjected to are different from a wild population.

And so even if those Christmas trees grew up big enough to set seed, it’s not the same [laughter]. They didn’t have the same life experience that the wild populations had over the millennia. Right? I mean, it’s different.

Travis: Right. Right. You’re selecting for vigor and a pretty limited number of traits. That means you’re potentially removing traits that at a genetic level are extremely important for resisting disease, adapting to something as big as climate change. So yeah, we try to avoid this in cultivation by randomly potting up seedlings [above], rather than just selecting the strongest ones.

We keep our accessions to a really small number and have multiple accessions throughout the garden. We avoid planting things next to one another. We do deadhead and we practice cultivation techniques that would prevent hybridization. And even in the design itself, so creating defined groupings of plants can help maintain that accession, or that particular grouping of plants in its location, so that it doesn’t spread. And at that point, the data starts to get a lot fuzzier and we can’t track that plant as best as we can.

Margaret: Right. So you were talking about collecting seed and we were talking about collecting seed, and the importance of collecting seed from lots of different individuals in a population, not all the seed from one tree or two trees or whatever. And you actually literally collected seed [laughter]. I saw a picture of you up at the top of a Fraser fir tree. I don’t know where it was, but in the wild so to speak. Actually you’re an arborist, so you were actually called into service to collect the seed. Yes?

Travis: Yeah, that’s right. The collection protocols that we use are developed by the group called the Center for Plant Conservation, and really the numbers we were looking for were at least 50 individuals with a target of 10,000 seeds.

Margaret: Wow.

Travis: And that, defined by the CPC, represents a really good collection, a good sample with hopefully as much genetic diversity across that population. And so we do try to spread out throughout its range. Like if we’re in a particular population, we try to collect from across its range, and from several populations within its range.

In the case of the Fraser fir, one of the healthier stands of the Fraser fir exists in Mount Rogers in southwestern Virginia. So we focused our collection efforts there. It’s another state park called Grayson Highlands. These have really healthy stands of mature Fraser fir, which indicates that this population has some resistance perhaps to the adelgid. That’s not really understood. But we focus our collection efforts there, again with the target being 50 individuals minimum. And we want to collect 10,000 seeds.

So we go out into the field and we use GPS. We’re pretty meticulous about collecting data in the field. And so we take notes on the habitat-associated species, the aspect, the soil types, all these different environmental factors of the site that we’re on. And then we just make the collection. As an arborist, as a climbing arborist, scrambling up 50 Fraser firs was a pure delight [laughter]. We spent about two or three days working on that collection.

Margaret: How tall?

Travis: Meanwhile we were able to collect opportunistically. I think they were about 30 or 40 feet. The species maxes out around 50 realistically. For the taller ones, ropes are required, but for some of the smaller ones, they have a very step-ladder kind of habit. So it was not too challenging to hike up to the top, grab a cone or two, put it in a paper bag, and then just send it down. It was wonderful. And it smelled amazing, the sap on the cone.

Margaret: The sap, right [laughter].

Travis: Really fragrant. I was covered in sap most of those days.

Margaret: As are the seeds. I think the seed cavities are resin-filled, so they’re not easy seeds to clean, either.

Travis: Oh, they’re incredibly difficult to clean.

Margaret: Yeah. So I want to save some time, last few minutes to talk about some other projects that Missouri Botanical has worked on and some other things. So Missouri Botanical is not making a tree farm to grow these on, because you’re not in the right habitat. You’re not in the right zone, the right kind of soils, all these kinds of things for the native range. I know that like the National Park Service is doing a preservation plantation of the Fraser fir and some other efforts are going on. So there’s other institutions and so forth working on them.

But I just wanted ask about some of the other, isn’t there an oak, a native oak I think that you’ve been working on as well? Just another example of some of these projects quickly.

Travis: Yeah, for sure. So our efforts with the Fraser fir at this point are pretty limited to seed banking. We’ve had some interesting complications, some setbacks. But we’ve learned a lot about how to maybe collect better samples of the species for the seed bank. But you’re right—it’s not going to grow in our climate. So really, we’re playing the long game here. We’re one piece in the puzzle globally of other institutions and partners that are working to conserve this species. And that’s true for many of our target species.

You mentioned a scrub oak, Quercus arkansana, another project that we’ve been working on the last two years to collect mass genetic samples of Quercus arkansana. It’s a pretty restricted oak in the Southeast. We’ve had teams go out the last two years to collect acorns. [Q. arkansana, above, by Eric Hunt via Wikimedia.]

An interesting difference between the Quercus project and the Abies project are in the seeds themselves. Abies fraseri is a seed that can be put into long-term storage and a seed bank. Drying it, and then putting it into frozen suspension. Quercus is what’s known as a recalcitrant seed.

Margaret: Recalcitrant! [Laughter.]

Travis: The acorn cannot be put into long-term storage. That poses a challenge. If we’re not going to be able to seed bank this species, we must grow it. We must be horticulturists and conserve the species in a living collection. We do that by partnering with lots of other folks that want to have specimens of Quercus arkansana in their collection.

There’s a host of local partners, as well as other botanic gardens in the region, that we’ve partnered with to make a concerted effort to collect, to propagate, and then to cultivate Quercus arkansana in a living collection. Again, these are samples. They’re plants that we can display, but they’re also genetic repositories for future your restoration efforts to save the species.

Margaret: Right. I just want to shout out the incredible resources—even if people don’t live close enough to come visit the garden in St. Louis—the online resources are incredible. Like anytime I’m looking up a plant and I want to learn more, I put the name of the plant and then I put “Mobot,” M-O-B-O-T, for Missouri Botanical. So I’d put “Delphinium Mobot,” or whatever [laughter], and I get the Plant Finder, that incredible encyclopedia plants that you have. So there are a lot of other resources, even for people far afield, right, at Missouri Botanical?

Travis: Yeah. We have access to so many wonderful resources to do research. For the gardening community, the Plant Finder pages are indispensable. They’re full of great information on how to cultivate plants.

Another resource, if you’re interested in conservation and species conservation at botanic gardens, BGCI is sort of the main organization that helps facilitate botanic gardens to maintain viable collections of rare and endangered species. It’s something we’re hoping to utilize in the future so that we can maximize our efforts with other institutions that may also be working on a conservation project. That’s another great resource to learn more about what efforts are being made to conserve species.

Margaret: All right. Well then I’ll give the links to those as well as to the blog, where I always read really interesting articles, including the one that led me to speak to you today about the Fraser fir and its plight. So Travis Hall, thank you so much for sort of taking us on this journey. Happy holidays to you and good luck in the work. Thank you.

(Photos from Missouri Botanical Garden except as noted.)

MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 11th year in March 2020. In 2016, the show won three silver medals for excellence from the Garden Writers Association. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the December 27, 2021 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify or Stitcher (and browse my archive of podcasts here).

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