Scientists in Vermont have been intentionally infecting thousands of trees with Dutch elm disease over the summer. This initiative by researchers from the U.S. Forest Service and the Nature Conservancy aims to test the resistance of a new generation of elms bred from disease survivors against the fungus spread by bark beetles. This fungus has been devastating elm populations in the U.S. and Canada for many years. The ultimate goal is to restore areas where elms once thrived, gracing city streets and riverbanks.
The loss of elm trees over the years has been severe, says Gus Goodwin, a senior conservation planner at The Nature Conservancy. The experiment in Vermont and similar efforts in Canada hope to develop elm strains resistant to Dutch elm disease (DED) to combat its increasing threat in new regions.
In the past, Dutch elm disease wiped out thousands of elm trees in Fredericton, once known as the “City of Stately Elms.” University of New Brunswick professor Anthony Taylor, who has surviving elms on his property, notes the ongoing challenge of the disease affecting even these resilient trees. DED, spread by bark beetles, attacks the tree’s vascular system, leading to its demise within a few years of infection.
Efforts to control DED involve promptly removing infected elms to prevent further spread. However, past practices of removing healthy elms inadvertently reduced the disease-tolerant tree population. Cities are now adopting active management strategies to combat the disease, emphasizing community involvement in prevention measures.
While Dutch elm disease continues to threaten urban forests across North America, ongoing research projects like the Elm Recovery Project in Guelph and Fredericton’s city initiative are striving to enhance resilience against the disease through selective breeding and cloning of disease-resistant trees. These long-term breeding programs require patience as they aim to produce generations of disease-resistant elms to restore affected populations.
By fostering disease-resistant elms, researchers hope to create a more resilient ecosystem that can withstand the impacts of climate change. The gradual reintroduction of disease-resistant elms may offer a sustainable solution to ensure the survival of these iconic trees in the face of ongoing threats.