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Episode 1: Tree Species Restoration & Resistance Breeding

Produced and hosted by Jonathan Yales - 9 min.

Research Biologist Jennifer KochResearch Ecologist Kathleen Knight Research Ecologist Leila Pinchot Research Ecologist Charlie Flower with Podcast Producer Jon Yales.

In season one of Forestcast, entomologists showed us the ways we slow insects from attacking and killing trees. This season, we’ll meet another set of scientists, who have been attacking the issue of non-native invasive insects and pathogens from a different angle.

Chemicals and biological control can buy trees time, but they cannot completely control the non-native insects that are attacking trees that have never experienced these insects before. We need something on top of those controls, and these scientists, they’ve been working towards a solution — a long-term resistance.

What is it? Well, it’s simple. At least, a simple idea: use trees.

Jonathan Yales
So, where are we going?
Kathleen Knight
So, we are headed out to the elm plantation. So, we have two big fenced areas here—the fences are to keep the deer from eating our little trees because deer love elm.
Jonathan Yales
In season one of Forestcast, entomologists showed us the ways we slow insects from attacking and killing trees. Like, using chemicals, like with the spongy moth.
Dave Smitley
Bacillus thuringiensis is what it stands for. It's a product made from a bacterium. It produces spores that are toxic to when they ingest them, but it only affects caterpillars.
Jonathan Yales
Or, like, using wasps, like with the emerald ash borer.
Leah Bauer
These wasps are highly co-evolved to develop within a host and kill it. That's why we don't call them parasites, they’re parasitoids. It's sort of a specific term to an insect that specializes on eating other insects.
Jonathan Yales
This season—in season two of Forestcast—we’re leaving those entomologists behind, and meeting another set of scientists, scientists that have been attacking the issue of non-native invasive insects and pathogens from a different angle. Chemicals and biological control can buy trees time, but they cannot completely control the non-native insects that are attacking the trees. we need something on top of those control options. And these scientists, they’ve been working towards a solution — a long-term resistance. And, what is that long-term resistance? Well, it’s simple, at least, a simple idea: use trees.
Charlie Flower
The varieties on the left here were largely sourced from a collaborator in Michigan. So, he's a farmer in Michigan and an elm enthusiast, and so, he and his father would travel around the landscape of Michigan kind of identifying survivor elms. So, the majority of the material here on the left was sourced from those efforts, and we just inoculated them in 2018. You know, six-meter trees, so, you know, 20-feet, roughly.
Jonathan Yales
Whatever these special trees are, they’re not only facing insect problems, though. This season—and these elms right here—we’re dealing with another form of pest: pathogens, or tree diseases.
Kathleen Knight
As you're looking out here, you see a lot of stumps in between some of the trees, and those are the trees that didn't make it. So, they died after they got inoculated with Dutch elm disease. So, you can see how many trees in the planting don't make the cut, and are susceptible to the Dutch elm disease fungus. And then, these trees that remain, that you can see—the ones that haven’t lost their leaves yet this fall, [they] still have quite a few leaves, they’re healthy looking trees—they were able to survive.
Jonathan Yales
To combat these diseases—and to find a longer-term resistance than using chemical or biocontrol—these scientists approach the problem from a different angle. In season one, we approached the pests from outside the tree, by putting chemicals and other insects on top of the tree. This season, scientists approach the problem from inside the tree. And rather than responding to the problem in the middle of a tree’s life, when it’s already dying—as we did in season one—we’ll be attacking the problem at the beginning of the tree’s life—even before it’s “born,” even determining what tree is born. And, that’s why I’m here—in Delaware, Ohio, north of Columbus—to see these special trees, and to find out how the heck all this works.
Kathleen Knight
So, this is what we call the lath house. This first section of the lath house has Jennifer's ash trees. So, we can go in if you want.
Jonathan Yales
And how would you describe a lath house?
Kathleen Knight
So, the lath house is where we keep larger potted trees that don't need to be indoors in a greenhouse—they can be outside exposed to sunlight and the elements. We do continue to water these trees, so we're in the section here with the ash trees and they’re probably about eight feet tall, so it's a little bit of a jungle in here. We can go on into the elm tree section.
Jonathan Yales
I’m here with Kathleen, Leila, and Charlie—they’re ecologists—and their job involves two types of research: resistance research—helping breed these special trees, and restoration research—figuring out how to put these trees back into the environment to restore the species.
Kathleen Knight
The elms that were inoculated here and survived, and were the best performers here, are then the elms that get tested in these riparian plantings and urban plantings to test how they perform in those conditions. So, we know they perform well with Dutch elm disease here at this plantation, we want to know how they respond to compacted soils and salinity, and all of these other issues in a city.
Jonathan Yales
Now, these ecologists, they don’t work alone. They work closely with a variety of scientists, and one in particular—geneticists—when working on the resistance research side—the breeding side. And Jennifer, the geneticist of this group, was out of town today. But, Jennifer and this group’s breeding work was still all around us, yet, invisible, because the work of a breeder, it’s hidden, hidden in time.
Jonathan Yales
And, how many years did it take for these pots to get here, roughly?
Leila Pinchot
How many years, like, including the research that went into them? Or, how old are they?
Jonathan Yales
Both.
Leila Pinchot
Let's see, RV-16... I think these…
Jonathan Yales
You can say, ‘I don’t know,’ but...
Leila Pinchot
No, I'm going to try, I'm going to try.
Jonathan Yales
As you know, trees live on another timescale than humans—a much longer one. And, to breed, your job is to infiltrate that timeline, and to understand it. And by understanding that timeline, you can begin to fiddle with it. Fiddle with time, and with the future. The future of that plant, but also the future of our planet. Genetics allow us to make better trees, make a better world, and do it all by fooling our forests. And, today, behind each one of these “better” trees that sat around us, sat time—and a lot of it.
Leila Pinchot
No, I'm going to try, I'm going to try. These were cross progeny that were probably planted in the ‘90s, is my guess. And, so, they were tested in the, probably, early 2000s. And then we made cuttings of them, I believe, about two years ago. So, these are almost 30 years in the making, to get to this point.
Jonathan Yales
It’s that time—those 30 years of research—that we’ll be diving into this season with Jennifer and her resistance work.
Jennifer Koch
The Forest Service—and, especially, the [Northern] Research Station—loves to lump restoration in with resistance breeding.
Jonathan Yales
But, we won’t forget about Kathleen, Leila and Charlie, and their restoration work, either.
Jennifer Koch
To me, restoration—especially, with these species that are threatened with extinction—isn't even on the table unless you have resistant planting stock.
Jonathan Yales
We’ll be crossing back and forth between the two types of research—resistance, and restoration—to see how resistance research breeds restoration research, and how all of it leads to better forests.
Jennifer Koch
It can be done, this is a problem that can be solved, and breeding can solve it.
Jonathan Yales
See you next Tuesday for Part 2 of Backcross.
Jonathan Yales
This episode was produced, written, and edited by me, Jon Yales. My editors at the Northern Research Station were Jane Hodgins, Sharon Hobrla, and Gina Jorgensen. Special thanks to Kathleen Knight, Leila Pinchot, Charlie Flower and Jennifer Koch of the Northern Research Station. And thanks to the Michigan State University Department of Entomology. Thank you for listening to Forestcast. It's god to have you back. If you like the show, help spread the word by giving us five stars in Apple Podcasts, and telling two friends or colleagues about this. Thanks for listening. And, this podcast is produced by the USDA Forest Service. The Forest Service is an agency of the U.S. Department of Agriculture, which is an equal opportunity provider, employer, and lender. And this episode’s music was by Blue Dot Sessions. See you next week.

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