Extinction rates have accelerated around the globe. Changes in climate and habitat loss, in particular, are driving more animals to lose their homes and access to the food they need, leading to endangerment of thousands of plant and animal species.
Plant species in the U.S. are not immune to these changes. When it comes to trees in particular, however, their risks have been relatively unknown. Or, at least, a bit outdated. A team of researchers from several organizations, including the Morton Arboretum in Lisle, Illinois and the U.S. Department of Agriculture Forest Service, has recently completed a comprehensive assessment of all 881 trees native to the contiguous 48 U.S. states. This assessment may serve as a roadmap for supporting future conservation efforts of these tree species.
Their findings are published in a recent issue of Plants, People, and Planet.
This tree threat assessment represents the end product of a five-year research effort. The team focused on extinction risks for each tree, diversity patterns across geographic areas, and the key threats to trees. The team used the Global Tree Assessment definition of a tree to guide their work. Researchers used their findings to build a checklist that could be used to monitor these tree species in the future and guide future conservation efforts.
One of the most stark findings from this new threat assessment was the revelation that between 11% and 16% of tree species in the 48 states are at significant risk of extinction. Researchers point to invasive species as one of the most common threats to these tree species.
The team also showed that the two most common groups of trees (oaks and hawthorns, representing about 169 species of the total 881 surveyed) also had the most threatened species of trees.
Finally, the research team built a methodology that would enable more effective data sharing in the future to improve conservation efforts.
Aside from providing vital oxygen, trees are also a vital part of any ecosystem. They provide food and permanent habitats for many species of plants and animals, which in turn benefits humans. Healthy balanced ecosystems always benefit humans, so the threat to a significant portion of tree species is troubling.