According to a first-of-its-kind assessment, one in six native tree species in the contiguous 48 states is threatened with extinction.
What you need to know
- According to a first-of-its-kind assessment, one in six native tree species in the contiguous 48 states is threatened with extinction.
- The most common threats to Native American trees are invasive insects and diseases, climate change and extreme weather, changes in habitats and uses of biological resources such as logging, the analysis said.
- According to the researchers, the Global Tree Assessment aims to assess the threats posed to all of the world’s approximately 60,000 tree species, but most species native to the continental US had either never been analyzed or the assessments were out of date.
- The researchers concluded that 11-16% of tree species are threatened with extinction
The most common threats to Native American trees are invasive insects and diseases, climate change and extreme weather, changes in habitats and uses of biological resources such as logging, the analysis said.
The findings are published in the journal Plants People Planet.
According to the researchers, the Global Tree Assessment aims to assess the threats posed to all of the world’s approximately 60,000 tree species, but most species native to the continental US had either never been analyzed or the assessments were out of date.
To close the information gap, researchers from Botanic Gardens Conservation International-US, The Morton Arboretum and NatureServe conducted a five-year study to assess threats to all 881 native tree species in the lower 48 states. Scientists collaborated on the project with the US Botanic Garden and the US Department of Agriculture’s Forest Service.
The researchers concluded that 11-16% of tree species are threatened with extinction. They said the findings could help protect the species from extinction.
“Trees form the basis of many of the world’s terrestrial ecosystems,” Sean T. O’Brien, president and CEO of NatureServe, said in a statement. “Understanding which trees are threatened and why is critical to informing conservation of trees and ecosystems across the country.”
Oaks and hawthorns dominate the US tree flora, with 85 and 94 native species, respectively. They are also the most endangered species, with 29 oaks and 17 hawthorns identified as threatened, according to the paper.
Florida (45) and California (44) have the highest number of threatened tree species, the researchers found. Trees that either evolved in the contiguous US or are found only here are concentrated mainly in the southeastern part of the country, Texas and California, they noted.
Among the biggest threats to the trees are the emerald ash borer, an invasive insect whose larvae have decimated the ash population by feeding on the living tissue under the tree’s bark, and the disease known as “laurel wilt” that attacks three types of evergreen trees. .
While such insects and pathogens are considered the biggest threat to tree species, climate change, including an increasing number of wildfires, is likely to worsen the situation, the study said.
Ironically, the researchers note that “conserving and restoring native trees and forests on a nationwide (and global) scale has great potential to mitigate climate change, particularly through carbon sequestration.”
Ninety-five percent of native tree species in the U.S. can be found in botanical gardens, arboretums or seed banks, scientists said. However, 17 species are not being conserved outside their natural locations, putting them at risk of one day becoming completely extinct.
The federal government currently recognizes only eight tree species in the US as endangered or threatened, which carry varying levels of protection and regulation.
“This assessment advances our understanding of the threats facing America’s native trees and will help focus the conservation efforts of public gardens, federal agencies and conservation organizations,” said Susan Pell, acting executive director of the Botanic Garden. of the USA.