Emerald ash borer (EAB) treatment and prevention is crucial for protecting Denver's ash trees. Early detection is key, as treatments are most effective when applied before significant damage occurs. Systemic insecticides, injected directly into the tree or applied to the soil, can provide protection for several years. However, not all ash trees are suitable candidates for treatment. Prevention measures include avoiding the transport of firewood, which can harbor EAB larvae, and regularly inspecting ash trees for signs of infestation. Working with a certified arborist can help homeowners and property managers develop a comprehensive EAB management plan.