Trees across the U.S. face dire threats, new report shows

A new report out this week warns that at least 1 in 9 tree species in the U.S. are at risk of extinction. Trees face a host of threats including invasive species, deadly disease and climate change. The data comes as part of the most comprehensive threat assessment ever collected on U.S. forests.

Read the Full Transcript

  • Geoff Bennett:

    It was President Franklin Roosevelt who said forests are the lungs of our land, purifying the air and giving fresh strength to our people. But a new assessment out this week paints a picture of the nation's trees in trouble. They face a host of threats including invasive species, deadly disease and climate change.

    It's come to this injecting trees to try and save them. The tools of the trade include drills, pesticides, hard work and a little hope, all in the quest to stop a tiny beetle from finishing off this ash tree. It's one of about 100 tree species in the U.S. now deemed at risk of extinction.

    Here on the edge of the Blue Ridge Mountains on the Appalachian Trail parts of the forest are in real trouble and likely can't be saved. And that's why land managers and scientists are trying to conserve what's left.

    Two of them were our guides for the day deep in this Virginia forest. Ron Hughes is a land manager and Johnny Townsend is a botanist for the state, just walking through the forest. So far, I've seen more dead ash trees and I've seen healthy ones.

  • Johnny Townsend:

    At least visually for a person who comes around and knew the place as they once did. They're going to see about half of the trees gone that they knew.

  • Geoff Bennett:

    Not long ago, you couldn't see the sky under the canopy of trees here. Now there are gaping holes. This forests black and white ash trees are under attack from the emerald ash borer beetle.

  • Johnny Townsend:

    That's killed it over the last six or seven years and a lot of the places where the spores been, the trees have died and either fallen down or they're standing sort of skeletons.

  • Geoff Bennett:

    And when you say places where the bore has been, you can actually see it here.

  • Johnny Townsend:

    The larva go inside under the bark, and form these what we call galleries, this sort of U shaped squiggles around in there and they gouge out just enough of the growing layer in the nutrient layer or conducting a tree that they choke it off. And eventually, the thing dies sort of starve to death.

  • Geoff Bennett:

    And across the country. The ash isn't the only tree in trouble.

  • Wesley Knapp, Chief Botanist, NatureServe:

    Without trees. Our ecosystems are broken.

  • Geoff Bennett:

    Wesley Knapp is the chief botanist for NatureServe, a nonprofit whose extensive database of trees helped contribute to a new sweeping assessment of the state of native trees in the US.

  • Wesley Knapp:

    We had to first come to consensus on what trees are and we landed on 881 species of tree. So there's quite a diverse group of organisms. Because each species tells its own tale and interacts in nature in its own unique ways.

  • Geoff Bennett:

    The study found 11 to 16 percent of native trees are in danger of extinction, and invasive species and disease are the biggest threats, followed by climate change, severe weather logging and agriculture.

    Murphy Westwood, VP of Science and Conservation, The Morton Arboretum: I don't think we fully understood how, how big of an effort it would be.

  • Geoff Bennett:

    Murphy Westwood at Chicago's Morton Arboretum spent the last five years working on this first of its kind study.

  • Murphy Westwood:

    Before this report came out we didn't really have a strong understanding of the state of the country's trees and their risk of extinction. I mean, imagine a forest without a tree. Trees are also important to our everyday lives. They improve our air quality, they capture stormwater, they capture carbon, so they're a very strong and powerful nature based solution to the climate change crisis that we're facing. And they also give other co benefits like cultural value, spiritual value. They even increase the value of your home your property. They make our cities cooler.

  • Geoff Bennett:

    Many of the tree species identified as most at risk are in the southern U.S., Florida, Georgia, Alabama, Texas, and out west in California. Many are recognizable species Hawthorne, oak and pine, among others.

    That brings us back to the struggling ash tree. We trekked deeper into the forest off the trail and through streams to find one of the largest living black ash trees in the forest. Is the threat posed just by the insects or its climate change a factor here as well?

    Ron Hughes, Virginia Department of Wildlife Resources: A species like this which is actually a northern species and survives in a few places in Virginia where the climate is just right and that means a little cooler.

    When you start getting increases in temperature, then you start affecting that plant that likes a different climate. When you get a tree that is a very integral component of a forest, and it goes away. It's a disruption in the whole system. And there are microclimate changes that happen when you open a part of the canopy up.

  • Geoff Bennett:

    Into your point, I mean, we've got the sun beaming in right now. I mean, 5, 10 years ago, that wouldn't have been the case.

  • Ron Hughes:

    That's correct.

  • Geoff Bennett:

    In the 20 years since the emerald ash borer made its first appearance in the U.S., it's destroyed tens of millions of trees in 30 states, nature's deadly graffiti was all around us in Virginia, an example of just one of the threatened trees on the new list.

  • Wesley Knapp:

    This is about prioritization of our limited resources. I'm very hopeful that something that seems like maybe an academic exercise to figure out what the rare trees are, will yield on the ground meaningful conservation action.

  • Ron Hughes:

    I know there's a lot of battles out there a lot of tough ones, but that's the challenge of the job. And if we do everything we possibly can to benefit and to conserve, that makes me feel good. Even at the end of the day if I come back in and half of these trees we're treating are dead, at least I know that we have done the best we can to conserve it.

  • Geoff Bennett:

    In deep in the forest that conservation work goes on one tree at a time.

Listen to this Segment