The City is taking proactive steps to prepare for the impacts of the emerald ash borer (EAB), a non-native, invasive beetle that feeds on ash trees and eventually kills them.
Beginning in October, the City will preemptively remove approximately 150 ash trees from City-owned properties, including parks, open spaces and public facilities. These trees have been identified as potential safety concerns because of their proximity to homes, utilities, pathways and roads. Once infested by EAB, ash trees can decline quickly and become hazardous.
This work is part of the City’s multi-year EAB Readiness & Response Plan, adopted by City Council on August 4, 2026. The plan uses a combination of strategies—including selective tree removal, chemical treatment and leaving some trees in place—to manage the impacts of EAB.
By addressing higher-risk trees before they become hazardous, the City aims to protect residents, City staff and public spaces while managing the anticipated loss of ash trees throughout Lake Oswego. For more information provided by the City of Lake Oswego visit their site here.
What is EAB?
The emerald ash borer (EAB) is a non-native, invasive wood-boring beetle that feeds on and kills ash trees (Fraxinus spp.), including our native Oregon ash. White fringe trees (Chionanthus virginicus) and cultivated olive (Olea europaea) are also at risk.
EAB is now permanently established in Oregon and will inevitably spread to Lake Oswego. Once EAB arrives in an area, it cannot be eradicated – which means it doesn’t go away.
Read the City of Lake Oswego Emerald Ash Borer Readiness and Respond Plan.
