A specialist in forest health has expressed concerns about the City of Edmonton’s current strategy in battling Dutch elm disease, warning of potential long-term impacts on the city’s tree coverage. Since 2024, Edmonton has documented 16 cases of Dutch elm disease, with nine cases identified this year. Elm trees constitute around 22% of the city’s tree canopy, predominantly American elm trees renowned for their tall, upright stature and cathedral-like canopy that make them popular for urban landscapes.
Dutch elm disease, a fungal infection carried by bark beetles, obstructs the trees’ water transportation system, leading to wilting and eventual death. Presently, Edmonton is primarily focusing on removing infected trees and those within 20 meters of the affected trees as a preventive measure, even if they are healthy. However, Nadir Erbilgin, a forest health professor at the University of Alberta, advocates for the introduction of trap trees to target the disease at its source, the bark beetle.
Erbilgin suggests using trap trees baited with bark beetle pheromones to attract and eliminate the beetles, thus reducing the disease’s spread. He argues that the current approach adopted by numerous North American cities risks killing more healthy trees than the disease itself, potentially including trees resistant to the infection. Mike Jenkins, a senior scientist with the City of Edmonton, acknowledged that the city’s strategy has led to the removal of healthy trees, highlighting the need for a more targeted approach.
Jenkins mentioned that enhanced surveillance efforts have enabled early detection of the disease, aiding in containment. The city plans to incorporate trap trees into its strategy next year, focusing on Siberian elms. As many Siberian elms are resistant to Dutch elm disease, Jenkins emphasized the importance of pruning dead wood from these trees to prevent beetle emergence in the spring before implementing trap trees.
While Edmonton continues its efforts to combat Dutch elm disease, residents are urged to contribute by maintaining their elm trees regularly and arranging periodic inspections. Sarah Mendonca from Trusty Tree Services advised residents to watch for signs of wilting leaves, blue-tinted branches, and beetle-induced bark scratches. Elm tree pruning is prohibited in Edmonton between April 1 and Sept. 30, but full-scale removal is permitted year-round, with disposal options available at the Edmonton Waste Management Centre. Suspected cases of Dutch elm disease should be promptly reported to the city for proper management.
