Sustainability Environment

Dozens of tree species face extinction from insects, diseases and climate change: research

“Understanding what trees are threatened and why is critical to informing conservation for trees and ecosystems across the nation.”
The Associated Press/Stephen B. Morton

Story at a glance


  • A sweeping report published in the journal Plants People Planet assessed the health of the 881 tree species in the contiguous U.S. 

  • The recently released threat assessment found between 11 and 16 percent of all tree species in the contiguous U.S. are threatened with extinction, due to threats such as invasive pests and diseases.

  • Florida and California have the largest number of threatened tree species in the U.S., with 45 and 44, respectively.

A first-of-its-kind report shows more than 100 native species of trees in the lower 48 states are facing the threat of extinction due to invasive insects, diseases and climate change. 

A sweeping report published in the journal Plants People Planet assessed the health of the 881 tree species in the contiguous U.S. to improve the efficiency of tree conservation efforts. 

Researchers say up until the assessment was completed, most tree species in the U.S. were not assessed or assessments were outdated. The years of research was conducted by the Morton Arboretum, Botanic Gardens Conservation International and NatureServe, in collaboration with the United States Botanic Garden and the Department of Agriculture Forest Service. 

The recently released threat assessment found between 11 and 16 percent of all tree species in the contiguous U.S. are threatened with extinction, due to threats such as invasive pests and diseases, intensifying wildfires, urban development and climate change.  

According to the report, oaks and hawthorns make up most of the tree flora in the U.S. and thus were found to have the most threatened species. The report found 17 species of oaks and 29 species of hawthorns are facing the threat of extinction. 

Florida and California have the largest number of threatened tree species in the U.S., with 45 and 44, respectively. Florida is home to 342 species of trees, one of the highest in the U.S. alongside Texas. 

“Trees form the basis of many of the world’s terrestrial ecosystems,” Sean T. O’Brien, president and CEO of the nonprofit NatureServe, which collaborated on the assessment, said in a statement. 

“Understanding what trees are threatened and why is critical to informing conservation for trees and ecosystems across the nation.” 

Researchers note that most native tree species are located in an off-site conservation area such as a botanic garden, arboretum or seed bank, but at least 17 threatened species are not currently conserved in any botanical collections and “thus have no insurance policy against extinction.” 


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