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New Guidelines Help Cities Manage the Slow-Moving Wildfire that is the Emerald Ash Borer Invasion

Photo of a residential street with one side with Emerald ash borer-killed trees and insecticide-protected trees on the other

Emerald ash borer (EAB) is like a slow-moving wildfire spreading through urban forests and killing ash trees. City foresters need guidelines that can slow the insect’s spread and preserve a community’s investment in urban forestry. Northern Research Station scientists delivered practical guidelines that emphasize the importance of surveillance for EAB.

Emerald ash borer has killed millions of ash trees valued for shading streets, homes, and parks in U.S. cities. To meet city foresters’ need for practical management guidelines, Northern Research Station scientists developed a model that evaluates EAB surveillance and control strategies with the objective of maximizing the benefits of healthy trees. The model captures the dynamics of ash trees moving through different levels of infestation. Scientists calibrated and validated the model using 7 years of infestation observations in plots in northern Ohio and subsequently used it to develop the following management guidelines for the city of Burnsville, MN: 1) It is critical to apply surveillance immediately to find the infestation and then treat trees with low to moderate levels of infestation and remove highly infested trees; 2) Surveillance and treatment or removal actions should mainly focus on locations where the infestation has started; and 3) If the budget is not sufficient, the planner may need to forego removing highly infested trees in favor of treating low- and mid-level infested trees to save them and prevent new infestations. These guidelines emphasize the importance of surveillance before treatment or removal to maximize benefits from ash trees and reduce management costs.