U.S. Forest Service researchers test elm trees for disease resistance

Scientists from the U.S. Forest Service and The Nature Conservancy Vermont are working to restore American elm populations by using Dutch elm disease to identify resistant trees. During the summer, researchers injected 6,000 young elm trees with spores of the disease to test their immunity.

The surviving trees will enter a breeding program designed to increase the genetic diversity of disease-tolerant elms. These trees are intended for future restoration in forests, riverbanks, and residential areas. The project involves growing the newly propagated trees in a seed orchard for approximately 15 years until they can produce seeds for widespread use.

Dutch elm disease, a fungus spread by bark beetles, has killed tens of millions of trees in the U.S. over the last century by preventing trees from absorbing water. Protecting the species is considered vital for maintaining ecosystem hydrology and combating climate change.