Wednesday, August 24, 2022

Dozens of U.S. tree species threatened with extinction, study says


New research finds as many as 100 tree species in the United States are threatened with extinction due to the impact of climate change and stress from drought, wildfires and severe weather. 
File photo by Terry Schmitt/UPI | License Photo

Aug. 23 (UPI) -- Dozens of tree species in the United States are facing extinction from invasive insects and disease caused by climate change stresses that include drought, wildfires and extreme weather, according to a new report.

As many as 100 native tree species, including 17 species of oaks, 29 species of hawthorns, redwoods, American chestnuts, black ash, and white bark pine, in the lower 48 states are in danger of dying out, according to the study published Tuesday in Plants People Planet.

Researchers found out of the 881 tree species assessed, between 11% and 16% are threatened with extinction. Florida has 45 threatened tree species and California has 44, the largest numbers of any other state.

The research, conducted over five years by the Morton Arboretum, Botanic Gardens Conservation International and NatureServe, found most of the health assessments were outdated and many trees species in the United States had never been studied.

"It's easy to feel that gloom and doom because ... the scope of the crisis is really, really great right now," said Murphy Westwood, lead author of the study and vice president for science and conservation at the Morton Arboretum. "We're losing species before they even get described."

It's this big swath of life that's totally unstudied or understudied," Westwood said calling it "plant blindness," the tendency to overlook plants and focus more on animals. Currently, only eight tree species are federally recognized as endangered or threatened.

"Trees form the foundation upon which most of the world's terrestrial ecosystems and biodiversity depends. They provide food and habitat for countless plant, animal and fungal species," the study says. "They sequester carbon, regulate hydrological cycles, clean pollutants from the air and support people's mental and physical health. Trees provide timber, food, fiber and medicine to humans and hold great cultural and spiritual value."

The researchers point to climate change for the rise in threatened trees saying trees stressed by drought, wildfire, pollution, floods or other extreme conditions open the door for invasive insects or fungi.

"There are trees that have been living in locations for hundreds and hundreds of years and suddenly they're dying now," said Stephanie Adams, in charge of plant health care at Morton Arboretum.

Botanical gardens and arboreta will play an important role in conserving threatened tree species. But researchers say at least 17 threatened species are not currently conserved in any botanical settings.

"Growing living trees in botanical collections is a critically important conservation tool, in the absence of seed banking as an insurance policy against extinction," the study said.

Planting native tree species in our gardens will also help, Westwood said. "We have a narrow and rapidly closing window to take action."

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