The giant American chestnut tree all but disappeared 70 years ago, killed by a blight that struck at the turn of the last century. By 1950, an estimated four billion of these magnificent trees were gone from our Eastern forests, and the tree, once dominant, is considered functionally extinct. We talk with researchers and volunteers who are working with promising new technologies to restore the American chestnut tree. There are still wild remnants of the tree in our forests - could you identify an American chestnut tree if you happened upon it?
Airdate: Tuesday, July 28, 2020
Listen to the conversation.
GUESTS:
This Granite Geek article in the Concord Monitor inspired us to look into American chestnut tree restoration:Breeding isn't resurrecting the chestnut tree; genetic engineering might.
Here's information from The American Chestnut Foundation:Why Bring Back the American Chestnut?
This transcript was machine-generated and contains errors.
Laura Knoy: From New Hampshire Public Radio, I'm Laura Knoy and this is The Exchange. The once dominant American chestnut all but disappeared 70 years ago, killed by blight that struck at the turn of the last century and despite many efforts to restore the trees since then, researchers have struggled to produce a blight resistant American chestnut. But now some are looking to new technology to turn this venerable tree's fortunes around. And today, on The Exchange, we ask, can we bring the American chestnut back?
Laura Knoy: Our guests are Kendra Collins, New England regional science coordinator for the American Chestnut Foundation. Also Thomas Klak, University of New England, professor of Environmental Sciences and vice president of the Foundation's Maine chapter, and Doug McLane, president of the Vermont/New Hampshire chapter and involved in local pollination efforts. And welcome to all of you. And Doug, I want to start with you. Why restore the American chestnut? What is it about this tree that makes it so great that you think it's worth all the effort?
Doug McLane: Boy, that's a that's a big question. And good morning, Laura. Nice to be here. The best analogy I can give to somebody is if we were trying to tell our grandchildren that we used to have a really cool tree called a Sugar Maple and it was beautiful and it gave sugar and if they nobody had ever seen a sugar maple, it would be hard to describe how grand it was. And the same with the American chestnut. Very few of us, anybody under 90 years old, has really never seen a good stand of wild American chestnut. So we have to go by the historical record that they were the most dominant tree in north eastern North America, the most dominant hardwood. And there are all kinds of reasons that I'm sure Tom and Kendra will go into. But there are hundreds of reasons for trying to bring back the American chestnut.
Laura Knoy: Well, and just remind us, Doug, how dominant it was. The descriptions are pretty remarkable.
Doug McLane: The most common and probably the best one is the range of American chestnut used to be from Maine to Georgia, and they said a squirrel could travel from Maine to Georgia on chestnut trees without ever touching the ground. There were approximately five billion trees that died, all within a period of one human generation.
Laura Knoy: And huge trees, right Doug, Like huge, huge around and wide wide canopies. Just to remind us how magnificent these trees were.
Doug McLane: Yeah, they were. They were called the redwoods of the East, although I think like most trees, probably most of them were what we would think of as a large oak tree. And some of them got massive with five and six foot diameter bases.But the main thing was that they were the most important food for the forest, mast food. And so they for that deer, turkey, bear, Native Americans, settlers and they're still delicious to eat. I think kind of the best way to someone's heart is often through their stomach and they are delicious.
Laura Knoy: Well, and Kendra you recently wrote a top ten reasons why the chestnut is worth restoring. In addition to what Doug said, what other reasons would you add, Kendra?
Kendra Collins: Well, the American chestnut is a great species for forest biodiversity. It's as Doug mentioned, it's a great species for wildlife. It provides shelter. It provides food. At different growth stages it provides different kinds of habitat. So getting these trees back into the forest would be really beneficial to eastern forests, especially in the face of so many other important tree species declining. This is a really hopeful effort from a human use standpoint. There's a lot of great uses for chestnuts, a great timber species that grows tall, straight up and limbless for the first 50 or so feet. So from a timber perspective, it's a dream. It's very rot resistant wood so a variety of uses there. Settlers used it for log cabins. Most of the tobacco barns you see in Connecticut are made out of chestnut, split rail fences in the Smokies are original chestnut. So it's a great timber species. You can also definitely get some great carbon sequestration benefit out of chestnuts, a long lived and fast growing hardwood. And from a reclamation standpoint, it can grow on pretty marginal sites. It's been used in the central Appalachians for a lot of mine land reclamation. But I think the biggest reason is just to show that we can save a tree species. There's a lot of other species in decline. The effort for chestnut has been ongoing for almost one hundred years now. And we're really seeing some hope at the end of the tunnel. And we're really looking to our story, too, to prop up some of these other species like ash and elm that are declining.
Laura Knoy: Well, I want to ask you all a little bit later about how your efforts to restore the chestnut might translate into efforts to save these other tree species that we all love in New England and that we hear are struggling as well. But what about the the tree's ability, Kendra, this is interesting to me, and I did not know this until yesterday, this particular tree's ability to survive and thrive in poor soils. Why is that so important right now, especially in the eastern United States?
Kendra Collins: Well, it gives us a lot of options for where to plant chestnuts, it's, you know, generates a more of a general species in terms of where it can survive. But as I mentioned, in the central Appalachians, it's been used quite a bit for mine land reclamation. So when you have these mine spoil sites that are generally just sort of a mineral substrate, kind of crushed up rocks, really, you can plant chestnuts and they will actually grow and help get a new forest going in these sites, which is a lot more beneficial to the environment, to the native species, than reclaiming it into, say, a grass field, which is often what is happening. So that would be the big, big one for me.
Laura Knoy: Tom, it's been said that the chestnut died out before we really had a chance to study and appreciate fully its ecological importance. But the famed forester Gifford Pinchot said he believed this tree's ecological importance was as impressive as the tree itself. That's a quote that you see a lot. What do we know, Tom, about the role that this tree used to play in forest ecosystems?
Tom Klak: Good morning, Laura. Nice to be on your show. Yeah, it was super important ecologically. The science of ecology was not as advanced back then as it is now. We know six species of moths went extinct when the chestnut suffered the blight because of the chestnut was their host plant. I'm sure there are many other relationships that got lost in the destruction of the blight, some of the studies that have been done lately to ensure --we'll get into this issue of the transgenic chestnut -- but studies have indicated when when tadpoles are fed chestnut leaves detritus, they do better than they do on other species that have replaced the chestnut like maple and beech. So it gives you a little bit of an indication of the richness of the forest that's been lost. They said that in some places, the chestnut burrs which contain the seeds would be one foot deep or more in the forest floor come October. So you can imagine the wildlife benefits of that. And no doubt that wildlife was much more abundant back when the chestnut thrived.
Laura Knoy: You know, give us a little bit more on that tadpole study, Professor Klak, because I think it does demonstrate what was lost in terms of forest health, which we're all told is so important right now, especially given climate change. Give us a little bit more on that tadpole studies, how the tadpoles were healthier eating the leaf litter of chestnut trees than other trees.
Tom Klak: Right. Yeah, so that connects us with why we were studying this, and it's our colleagues at State University of New York in Syracuse and the Environmental Science and Forestry College. So they have been testing in many different ways how the what we call the transgenic chestnut -- we'll talk more about that in a minute, that's the one that has the wheat gene inserted to give it blight tolerance -- how does it perform compared to the wild chestnut tree? And in all the studies, the evidence shows that it performs exactly the same. No difference. But a kind of surprisingly out of that work was the fact that the tadpoles actually did better on chestnuts, be they your wild chestnuts or the ones with the wheat gene inserted, which, again, was a revelation. It wasn't the point of the study, but it gives you a little bit of an indication of the important ecological relationships that we've lost and how the forest has suffered. Certainly they've suffered just from from not having the food of the chestnut in fall and into the winter. But there's many other things that I'm sure we're going to find out when we bring more and more chestnuts back.
Laura Knoy: Wow. I find that fascinating. Kendra, what does that suggest to you? Again, these tadpoles being a lot happier and healthier, I guess, eating chestnut left-over than maple or other type of leaf litter?
Kendra Collins: Well, I will admit, I am not a tadpole expert either, my background is in forestry and specifically American chestnut. But, you know, I think ecologically what that says to me is that this was a food source that was very abundant and available to these species of frogs and that they developed the ability to thrive with that food source.And having lost it, they found other species that they can eat. But having chestnut back might be might make them even happier.
Laura Knoy: Doug, I have to ask you a very basic question, and we're on the radio, so you're going to have to use your best descriptive skills. Would we recognize an American chestnut if we saw it?
Doug McLane: Boy, that's yeah, that's a great question. You certainly would if you belong to the American Chestnut Foundation. Well, my wife sometimes doesn't even like to drive in a car with me because I'm looking more at the trees for chestnut leaves than at the road. And it's a very distinctive leaf and a very distinctive shaped tree and also the fact that it's the very last native tree to flower. So they were just flowering a week and two weeks ago, long after the oaks and the elms and the maples have flowere. So it's fairly easy to pick out a wild American chestnut. But the sad reality is only one out of, whatever, ten thousand ever makes it to flowering stage. So you kind of have to look at the leaf and not for the flowers. And yeah, once word gets around, it's actually, it's a contradiction. We say there are very few chestnuts left. There are a lot of chestnuts growing out there. It's just that very few of them make it to the reproductive stage, which is what they would need to survive without human help.
Laura Knoy: So how far do they make it, Doug, like 10 years or 15 years?
Doug McLane: Oh, there are quite a lot of them that are 50 and 70 years old. There is a surprising number of large surviving American chestnuts. But the idiosyncrasy that they only reproduce, even though every tree has a male and female flowers on it, they only reproduce if there's a second tree fairly nearby. So the odds of having them grow into reproductive stage and having two of them close by is rare indeed.
Laura Knoy: Interesting. And you know, when I was a kid, we had a big, big chestnut tree in the backyard. But I'm guessing that was a different kind of chestnut. So there are other chestnuts, right? Like how can you tell the difference?
Doug McLane: Well, well, no. See, it's by name only. In other words, the horse chestnut is really not even related other than being a tree. But most people who work with horse chestnuts in their neighborhood and the burr looked very similar to the nuts that boys like to throw at each other and stuff are very similar looking. They're in inedible in a horse chestnut.They're very edible in an American chestnut. So really, most everyone that thinks they've seen a chestnut tree has seen a horse chestnut, which is an import from Europe, although the Buckeye from Ohio and areas like that is a native, a native. So, yeah, very few people have really seen a healthy big American chestnut tree.
Laura Knoy: Well, I want to remind our listeners that you can join us with your questions and stories about the American chestnut. That's what we're talking about today on The Exchange and the many, many efforts to restore these trees since they were not completely, but mostly wiped out in the last century. So all of you have made the case as to why it is worthwhile to restore this tree. And Kendra, that gets into the American Chestnut Foundation. When did this group get started and what's your approach now toward restoration?
Kendra Collins: Sure, so the American Chestnut Foundation is a little over thirty five years old, we were founded in 1983 and we were also lucky to piggyback off earlier chestnut restoration work, some other programs that had kind of gotten going and not quite made it as far as they had hoped. So we're the effort, I would say has been going on for about one hundred years, but our organization is a little over thirty five years old. Our initial approach was primarily a conventional breeding program, and since then technologies have advanced, scientific knowledge is advanced, and we've expanded that to this three pronged approach that we call 3BURR, which is the three B's are breeding, biocontrol and biotechnology, united for restoration, kind of a play on the fruit that the chestnut produces, which is a burr. It's very cute. And so our breeding work is conventional breeding. It is taking on at our Staff Research Farm in Meadowview, Virginia, as well as by our 16 state chapters throughout the native range. It's really how we get a lot of our work done is through our chapter programs. The biocontrol work is something we support but is done primarily by research partners in Maryland and West Virginia. And then the biotechnology work primarily encompasses the transgenic tree that Tom has mentioned. This was developed by Suny'S Environmental science and forestry school in Syracuse itself and the research team there led by Bill Powell. So those are kind of the three directions we're going. There's certainly a lot of overlap, especially between the breeding and biotechnology. Those biotech tools have really advanced recently. And so we are actually using a lot of biotechnology tools to better assess our breeding program and help us make any adjustments that we can to make that project, that piece of our work, more efficient and more successful.
Laura Knoy: So conventional breeding, most people know what that is, Kendra, we all learned about, you know, plants in high school biology, biocontrols, that's basically when you try to use another biological element to go after the blight. Is that right, Kendra?
Kendra Collins: That's what biocontrol is, yes. And the primary bio control option for chestnut or at least what's receiving the most attention and work is hypervirulence. And this is a case where there's a virus that actually reduces the virulence of the fungus and therefore makes it less pathogenic on the tree. And that just gives the tree a little bit of an edge and we're hoping enough of an edge that it can survive. So it's certainly a worthwhile avenue.
Laura Knoy: Well, and coming up, we'll talk about the third leg of what you mentioned, biotech. There's a lot going on there and sometimes it's controversial. I also want to let listeners know that we have an amazing old picture of these trees on our Web site that gives you a sense of just how huge they could be. Come check it out at NHPR.org/Exchange. Today, a new chapter in the long effort to restore the American chestnut. As we've heard, these giant trees once dominated Eastern forests, but since the 1950s, they've been considered functionally extinct. Now, though, some researchers feel they're closer than ever to restoration. After many decades. We're finding out more and hearing from you. What legends have you heard about these trees that were so important to Eastern ecosystems and communities? How much effort do you think should be made toward restoring them, given the many other challenges that our forests face? With us for the hour, Kendra Collins, New England regional science coordinator for the American Chestnut Foundation. Also Thomas Klak, University of New England Professor of Environmental Studies and vice president of the Foundation's Maine chapter, and Doug McLane, president of the Vermont/New Hampshire chapter, who's also actively involved in local pollination efforts. And Celia in Thornton is calling in. Hi, Celia. You're on the air. Thanks for being with us.
Caller: Hi. Good morning, Laura. I just happened to wake up very late this morning and heard your show and leapt out of bed and called right away. I live near the Welch-Dickey trailhead surrounded by National Forest in Thornton and five years ago when I worked for the, volunteered for the Squam Lake Science Center. I was given two seedlings of American horse chestnut or chestnut trees and told to plant them close to each other, which I did with no special attention. I now have two beautiful, maybe six feet tall trees close to each other that are doing very well, surrounded by the national forest. And I'm just wondering is a question for your expert, should I be doing anything to ensure there the fact that they will live and thrive for the next hundred years?
Laura Knoy: Wow. It's great to hear from you, Celia. And I love that you jumped out of bed and gave us a call. And Doug McLane, I'm going to throw that to you, please.
Well, that's fascinating for a lot of reasons. I hike the Welch-Dickey trail myself. We all do. Planting trees in the wild, you have a pretty good chance that they will live a long time. But you also have to realize that pretty much every single American chestnut that's planted will die of the blight. The ones that survive to old age, and we have what we believe is the Vermont New Hampshire champion right near us here up in Rumney. And it's probably reached, I can't quite get my arms around the trunk, and it's probably that old because it's in the edge of the blight range. And so there's not a lot of blight pressure. So to answer the question of what can you do to help your trees, as long as they have good sunlight, that's the most important thing. And I think you're off and running. Those trees will be fun to watch grow. Just don't be too disappointed if they do get the blight, because there's hope on the way with the work that the foundation is doing, we hope to be able to pass out blight resistant nuts in our lifetime.
Laura Knoy: Ok, so just to clarify then, it isn't that this tree completely died out. There are individual success stories, but they're fragile, Doug, is that it?
Doug McLane: Well, here's here's the contradiction. And it's a hard one to wrap your arms around. The blight does not kill anything in the soil. So the blight does not kill the whole tree. It kills what's above the ground. But the chestnut has a tremendous ability to re-sprout. So most of the chestnuts and here's a number that I think is amazing. There are an estimated three to four hundred million surviving American chestnuts east of the Mississippi. Most of them are re-sprouted from old trunks that died when the blight hit over one hundred years ago. So that the tenacity of the tree is amazing. I was hiking at the Appalachian Trail years ago down in North Carolina, and I saw chestnut trees all day, but most of them in the one to two inch range. They just very seldom get big before the blight hits them. So the genetic diversity is out there. But what isn't out there...it's a little bit like somebody who saw the last surviving passenger pigeon in the world in the Cincinnati Zoo in the early 90s and hundreds, the species wasn't extinct but was doomed to extinction. So it's a little bit like the American chestnut. It's not extinct, but it's not able to overcome the blight without some human help.
Laura Knoy: Ok, well, Celia great to hear from you. And let's take David in Canterbury. Hi, David. You're on the air. Welcome.
Caller: Hey, good morning. Boy, I love these kind of shows. I have two native. I was cutting firewood and I saw those chestnuts. The two of them are approximately four or four and a half inches high. They're going up 20, 25 feet tall. And I'm wondering what I can do. I thought, I had chickens with composted chicken manure put around to root out the drip line, help to boost their immunity to is there anything you can put into soil that will help them?
Laura Knoy: Wow. And I love this question. Kind of relates to Celia was saying, what can I do to help these, you know, these few remaining trees survive? Kendra, do you want to jump in?
Kendra Collins: Yes, sure. You know, I don't think that fertilizing them is going to help with immunity, but certainly chicken manure is going to have a lot of nitrogen. Chesnut eats up nitrogen. So if you wanted to grow fast, go for it. They would appreciate a little snack. The one tool for landowners that have chestnuts that they want to keep going. The assumption is that these are wild American chestnuts with no tolerance to the blight. So there's one tool you can kind of keep in your back pocket, and that's called mud packing. You can actually, if you monitor your trees for the presence of light cankers, which are fairly obvious, they'll look like sort of sunken damage spots on the stem of the tree. The fruiting bodies of the fungus are bright orange. So you'll see those, they are about the size of a pinhead, but you'll see a lot of them in those cankers and they they attack the living tissue under the bark and just work their way around whatever system they land on, whether that's the main trunk or a branch mud-packing, you can actually cut back that canker and put a mud compress on that area, wrap it in plastic, and it should kill an individual canker.
Kendra Collins: Now, this is a great tool if you catch the canker relatively early before it's girdled half the tree, you're not going to go mud-pack every tree in the forest. So it's not a solution for your organization to restore the species, but it can keep trees on your property going for a little bit longer.The only other thing I would add is that if anyone does have chestnut trees on their property, we would love to hear about them. One of the ways that we incorporate new trees in our program is by getting reports from landowners and interested citizens that might find them out hiking. We have some great resources on our website, ACF.org, for identifying the trees, for getting a form,for filling out a form to send in with a sample and all those to actually come to my office. And I'm always happy to look at more of them.
Laura Knoy: Well, and David and Celia, we always have links on our website to these resources. So you can go to our website as well. It's NHPR.org/Exchange. And again, check out the picture of these huge, huge chestnut trees from must be more than a hundred years ago that we've got there, too. It's pretty amazing. Thank you for calling in, David. And a couple of emails I'd like to share with you. Lee in Westmoreland says when are transgenic trees are likely to be available to buy at something like a garden center, I want to address that. And then Jeanne in Saco, Maine, writes in, should we be concerned about genetic engineering and its effects on the local environment with the chestnut restoration project? So two great comments from our emailers. And to you first, Tom, I know you've been working on some of this transgenic research at the University of New England. So to Lee's point first, when might transgenic trees be likely to be available?
Tom Klak: We we don't know that ourselves, because the decision is going to be made by three federal agencies that are evaluating the transgenic tree, so it's right now a regulated item. The argument, the petition, has been submitted to the particularly to the Department of Agriculture to get to the nonregulated status. So it's up to them to make a decision. It's worth noting that the USDA will soon have a public comment period where your listeners can can chime in about the transgenic chestnut. And we don't know exactly when that's going to happen, but USDA tells us it's going to be soon. So it has to go through the regulatory process and after that, then there will be opportunities for dissemination.
Laura Knoy: So before we get into the concern that Jeanne raises, and I have another email, too, that raises a similar concern. Just a little backdrop, please, Tom. So you mentioned earlier a wheat gene that scientists have been breeding into the American chestnut that seems to be working. This is after many years of traditional sort of crossbreeding or hybrid breeding with a Chinese chestnut tree did not work. Is that a correct summary, Tom?
Tom Klak: Yes. The we talked earlier about the importance of biotechnology in science in general and advancing our understanding and ability to deal with problems, especially a problem like this that we created. It's worth noting, why do we have why why has the most important tree of the eastern United States going functionally extinct? Well, we accidentally imported this lethal pathogen from Asia when people brought in the Japanese chestnut and the Chinese chestnut. So that's how it got here. So we need to think about, well, how do we reverse that? So what we've discovered with with biotech and Kendra mentioned this, we've been doing a lot of revealing work with genomics. And what that has revealed is that the Chinese chestnut tree, which has the ability to tolerate the fungal blight, it's a multiple gene process that allows the Chinese chestnut tree to tolerate the blight. Up until very recently in the genomic revelations, it was thought it was only two or three genes that mattered on the Chinese tree. Now we know it's many more genes than that. So that's the issue right now of how one would move a great number of genes from the Chinese tree over. The other approach, and this is the biotech approach, is to identify a single gene that can allow the American chestnut tree to tolerate the blight.
Laura Knoy: It turns off that that lack of resistance....Go ahead, Tom.
Tom Klak: Yes, it detoxifies the acid. The fungal blight uses an acid to kill the American chestnut. The fungal blight doesn't need to kill the American chestnut, an important thing, it can survive on other dead material in the soil. And it does. And survive on the bark of the Chinese chestnut, on the American chestnut, as it has for millions of years in Asia when it has coevolved with the Chinese chestnut. So what the wheat gene insertion into the chestnut does is allow it to tolerate the fungal blight, doesn't kill it. The fungal blight can happily reproduce and function without killing chestnut trees. And so that's the approach that my students and I have been working on at the University of New England.
Laura Knoy: So I think to you next, Doug, but also you Kendra, but you Doug. What about Jeanne's concern and I've heard this elsewhere, concern that genetic engineering will have harmful impacts on the local environment if you were able to do this genetically modified American chestnut tree and it took off and it thrived, there is concern that it might put some other unknown materials out in the wild. And I just wonder how you feel about that, Doug.
Doug McLane: Well, that's a big question, no pun intended, but I might go out on a limb a little bit on this and give you a personal reflection, which is that the people that are concerned about biotechnology, I think certainly have their hearts in the right place and I actually identify with that a lot. I don't think we should willy nilly just think that we should fool with genes and Mother Nature. I think the chestnut tree deserves a definite special exception because it's talking about a keystone species that will likely go extinct without some help. So to answer your question. There's really not a... the downside of biotechnology is that it simply doesn't work, that the tree is not able to go back into our forests and compete against the large hardwoods that it has to become again a dominant species. The danger is not that it will somehow run amok and pollute other trees. Chestnut spread very slowly. They were the last species to come back north after the glacier retreated. They don't have lots of seeds like elm tree or a maple tree. They have a very large nut that's easy to keep track of and control. So if it doesn't work, we'll have to go on to the next thing but right now it is the the best hope we have for saving the chestnut tree.
Laura Knoy: Well, Kendra, get your thoughts on that, too, after a short break. So coming up, we'll look more at new efforts to restore the American chestnut. This is The Exchange on NHPR.org. Today, the decades long effort to restore the American chestnut, why it matters to both ecosystems and communities and whether a new chapter is at hand. We're finding out more and we've been hearing from you. And Kendra, Tom and Doug, just before the break, we were talking about a concern raised by a listener who was worried about the possible impacts of a transgenic American chestnut, one that has used biotechnology to be resistant to this blight that wiped out this species. And Doug, in response, you said you were not concerned that these trees would, quote, unquote, pollute the forest. I did receive an email early this morning from Steve Taylor from the Stop GE Trees campaign. It's long, so I won't read the whole thing, Steve, but thank you for writing in. He says that chestnut restoration project under the direction of researcher William Powell intends to release a blight resistant American chestnut into wild forest ecosystems. He says corporate backers of Powell and the American Chestnut Foundation support use of the iconic American chestnut as a strategy to break through longtime public opposition to FE trees. In other words, genetically engineered trees. And there's a couple other points he makes. But that is the main point concerned that these trees would irreparably harm natural ecosystems and also that this is just an excuse, a sort of nose under the tent for more genetically modified plants and trees. And it's a big, big controversy and a big concern. And Kendra, I'm going to let you jump in on that.
Kendra Collins: Sure. So first, I'd like to correct just the assumption that big Ag or big business is behind this effort, that is absolutely not true. The lab at ESF has received funding primarily from from philanthropic sources. The tree is going to be in the public domain. The effort behind this is coming from a place of wanting to help and repair an ecosystem. That out of the way, the safety of this is something that the researchers at ESF have taken very seriously.
Laura Knoy: And sorry to interrupt, but ESF is what, just remind us again?
Kendra Collins: SUNY's Environmental Science and Forestry College in Syracuse. That's where this transgenic tree has been developed in Bill Powell's lab.
Laura Knoy: SUNY is the State University of New York. Go ahead.
Kendra Collins: Yes. And the ESF.edu/chestnut website is great, if any listeners have questions or are interested to learn more about their project, they've got a lot of great information up. The gene from wheat was selected in part because it was assumed it would be effective at preventing the blight from killing the chestnut, but also because it had been shown to be relative or very safe. It's from wheat. It's in a lot of other plants that are already in the ecosystem that are consumed by humans on a regular basis. So it's not nearly as, scary, I guess, as others they could have chosen for folks who are a little uncomfortable with the technology, but they've also done a really great job of testing these transformed trees in comparison with wild type chestnuts for their partnerships with mycorrhizal fungi, for their tadpole feeding, for bee feeding on pollen, for a variety of things that would be stand-ins for how these trees would perform in the forest. Deregulation is actually really important for being able to test these trees. At this point anyone who wants to plant transgenic chestnuts has to do it under permitted conditions, which are pretty limiting. To be able to test these things on the landscape the deregulation is actually going to really be helpful, assuming it goes through because other research groups will have access to these trees to help us really determine if they're going to be able to be the tool for restoring the American chestnut. One other thing that I think it's important to remember is just because this tree is deregulated doesn't mean it's immediately going to be planted in the forest. We need to diversify this tree with a variety of backgrounds of wild American chestnuts so that we actually have a population that can go back into the forest and that's going to take a few generations of crossing. There are some tools we can use to make that work go a little faster, but it's not going to happen overnight. But we're going to have plenty of time to assess the program as it moves forward for its effectiveness.
Laura Knoy: Well, permitting processes can move slowly, regulate regulatory processes can move slowly. Trees certainly grow slowly. So, Tom, I guess I'll throw this to you. How has the fact that we've been in a pandemic since early March, people are not, you know, meeting in person? I guess people are going out in the field, but you can't go out in large groups. So how has the pandemic affected the work that you're doing, Tom, on the American chestnut and its restoration?
Tom Klak: Right now, the pandemic, of course, has affected everything, and I'm sure all our listeners, your listeners are thinking about that every day, every sort of common everyday activity is shaped by the pandemic. And all my students went home to their their home states when the pandemic struck back in March. We've been able to reconstitute though, I've been doing a lot of work alone in my lab and also in the field. As you mentioned, we can do work outside. And I've hired a student to work with me as an undergraduate, and is a graduate, and now lives in Maine. And he's been tremendously helpful. His name is Flynn Willsey. So we've made a lot of progress and what we've been doing is developing the pollen from the transgenic chestnut in the University of New England greenhouse and a plant chamber, a high intensity light chamber. And this relates to Kendra's point about the need to diversify the genetics because the transgenic begins as a clone and we need to bring a variety of different genetic mixtures together. That's why going back to an earlier point, it's worth underscoring that listeners can help by finding wild trees and growing them in their yards like some of the callers mentioned they're doing. So we need genetic diversity from the wild population, coupled with the wheat gene blight tolerance aspect in order to bring the tree back, because the wild tree has everything going for it except for the fact that the imported blight kills it. And so that's the one thing we're inserting. Otherwise, the transgenic tree is ninety nine point nine nine nine percent pure American.
Laura Knoy: So here's a question for you, Tom. You mentioned earlier about how traditional crossbreeding had not had the positive results that you had hoped for, given the complexity of all the genes from that Chinese chestnut that for a long time researchers had tried to cross-breed into the hardier, blight resistant American chestnut. And so that has been going on for a long time, has not given the results that were hoped for. There are concerns, though, about these genetically engineered trees. What about, Tom, the biocontrols that we talked about earlier, finding a way to stop the blight?
Tom Klak: Right. Kendra mentioned before that that's sort of the third leg of our approach, and it's more limited than the other two being the biotech approach and the the breeding approach because it only affects individual trees. So we can have some success with biocontrol and to keep a particular tree alive for a little bit longer, which is a good idea. But it cannot solve the problem of trying to bring back a tree that had perhaps four billion individuals throughout its eastern range. So I've used it myself to keep some trees alive that we've pollinated this summer. But it's not an overarching solution like the other two big, major thrusts of the American Chestnut Foundation.
Laura Knoy: We also touched on this earlier. And Doug, I'll throw this to you. You know, New England has other beloved trees that are threatened. The elm, the ash, the hemlock. We've done stories on those. How do you feel, Doug, about the argument that let's focus our research efforts, our research time, our research money on those trees that are still with us instead of trying to revive a tree that is mostly gone? What do you think, Doug?
Doug McLane: Well, you asked the one of us... that is a complicated answer because I'm almost as involved in American Elm restoration. It's a wonderful tree. That we all remember when we were younger. And the elm does have blight resistant varieties, so it's not nearly as crucial. The chestnut does not have, as much as we all hope whenever we find a big tree, ooh, maybe this one has resistance. They don't seem to, they all seem to get the blight. Many American elms reach large size and reproductive stage. So you're right. We have the the beach tree and the elm tree and the chestnut tree are all dealing with blights imported from Asia. And yeah, we have to think big. I do know that ESF is working on the American Elm with transgenics and who knows where this will lead. So the goal right now is to find one tree, which is the chestnut, and show that it will work and then we can diversify. Quickly, I want to remind the caller that called in and a lot of people that have a chestnut or two or three that they look after, what can I do for it? And Kendra had mentioned that probably a dose of fertilizer is not generally what they need. But one thing that is very, very helpful and easy to do, which is to put a big mat of woodchips. You can get them free from your local tree people that have...they're looking for places to dump them. Probably not bark chips that you get at a nursery, but actual hardwood, soft wood chips. If you put a big layer of them under a chestnut tree, it can help mimic the forest floor, which is what these trees want.
Laura Knoy: All right. Well, we have to wrap it up there. We could have talked a lot longer, but I do want to direct people to the website. There are more resources there and some pictures as well. And I really want to thank our guests for being with us. Kendra Collins, New England regional science coordinator for the American Chestnut Foundation. Thomas Klak, University of New England, professor of Environmental Studies and vice president of the Foundation's Maine chapter. And Doug McLane, president of the Vermont New Hampshire chapter. This is The Exchange on NHPR.
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What Will It Take to Restore the American Chestnut Tree? - New Hampshire Public Radio
