Biodiversity is declining. More than a million species around the world could go extinct by 2050. And man-made climate change means the problem is only getting worse.

Those are a few of the key takeaways from a United Nations report out later this month. A summary of the report was released Monday in Paris.

The report does not focus solely on animals. Trees and plants across the world are under threat, including some species in the Midwest.

Morning Shift talks with local tree experts about the UN report and their work cataloging and trying to preserve oaks, ashes and other trees native to the continental United States.

What was your overall reactions to the UN report?

Murphy Westwood: I have to say, I actually sadly was not very surprised. This is work that I have been doing for a few years now. We actually helped compile some of the threat assessment reports that were ultimately analyzed to come up with that number of 1 million threatened species. And so, we have found that — for example, for trees — 20 percent of the world’s tree species, at least, are threatened with extinction.

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Jenn White: Lydia, what about you?

Lydia Scott: I can agree with Murphy that it wasn’t a surprise. We have experienced significant losses here with emerald ash borer issues, and we have low regeneration of our native oak ecosystems. So it’s just part of development that we’re experiencing with the expansion of humans. So it revolves around not just the climate impacts but also the loss of habitat.

On other big takeaways from the report

Westwood: Trees and forests provide our ecosystem services … and that is the things like sequestering carbon that mitigates climate change, cleaning water, cleaning our air, providing food and timber and medicine. These are the sorts of things that I think are really important and I love that this report highlighted how important that is at an economic and basic livelihood level. And I hope that’s a message that people can resonate with.

White: Lydia, big takeaways for you?

Scott: I go back to what Murphy was just talking about. When we think about the impact that trees have on our everyday life and habitat in general, it really impacts our quality of life. 

While we may think of ourselves as living in an urban environment with just roads and sidewalks, we don’t often look up and appreciate the fact that we have trees and other green infrastructure within our communities that are helping us to live a better life … they also improve our economic conditions in our communities. They improve property values. And we know from studies now that they have a significant impact on our mental and physical health.

On local efforts focused on biodiversity

Westwood: My program focuses on tree species as the unit of conservation that we’re targeting … I target species because what is so important is to understand that it’s not just the number of trees that we have out there, it’s that rich tapestry of different tree species. 

So we do monitoring programs, we have on-the-ground species conservation programs, where we’re actually planting trees and trying to figure out what these threats are to species in the wild. And we compile these threat assessments that the UN report used to determine how many species are threatened. 

White: And there’s 21 here in Illinois.

Westwood: That’s right. Globally there are about 450 species of oak. So we’re completing the threat assessment for all of those.

So far we think about a quarter of the world’s oak species are threatened with extinction, but there are a lot of data-deficient species out there because they are poorly known, they’re in hard-to-access areas and we still have a lot of research to do to understand what these threatening factors are and even how many tree species we actually have. We‘re discovering new ones every year.

White: Now Lydia, as head of the Chicago Region Trees Initiative and Community Trees Program, you’re working with municipalities in our area to make sure we’re planting the right types of trees. Explain a little more about your work.

Scott: Our work was started as a basis from the 2010 tree census that was conducted by the Morton Arboretum and the [U.S.] Forest Service. And we found that the trees in the Chicago region were in a state of transition, where we have about 30 percent of all of our trees are invasive species — which is also another threat that was identified in the UN report. We know that we have very low species diversity, which is also a significant concern because we don’t want a repeat of the emerald ash borer problem … we lost 13 million ash trees in the Chicago region. 

On the importance of planting native species in Chicago

Scott: We know that native species are typically planted in fairly low numbers in the Chicago region and part of this is some misconceptions that people have. They often assume that oaks grow very slowly, so they don’t plant oaks in the landscape — and that’s not really true. They do grow much more quickly than people realize.

The arboretum has developed what’s called a tree selector tool that enables individuals who may not know about different species of trees to select different characteristics, such as ability to tolerate salt or drought, things that we would find in the urban environment, and enables them to look through a whole list of species that do well in those conditions.

This interview has been edited for brevity and clarity by Stephanie Kim. Click the “play” button to hear the entire conversation.

GUESTS: Murphy Westwood, director of global tree conservation at the Morton Arboretum

Lydia Scott, director of the Chicago Region Trees Initiative and manager of the Community Trees Program

LEARN MORE: Humans Are Speeding Extinction And Altering the Natural World At An ‘Unprecedented’ Rate (New York Times 5/6/19)

Nature’s Dangerous Decline ‘Unprecendented’; Species Extinction Rates ‘Accelerating’ (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services 5/6/19)

Oak Ecosystems Recovery Plan (Morton Arboretum)