Oregon Field Guide: Threats to Trees from the Emerald Ash Borer Beetle
Co-written by Jordana Leeb
A new Oregon Field Guide - https://www.pbs.org/video/emerald-ash-borer-8f8gtj/ - shares information about the Emerald Ash Borer beetle in Oregon. The Concordia Tree Team's Jim Gersbach helped work on the segment.
Oregon Field Guide published a new video in June 2025 about the devastating beetle’s arrival and threats to ash trees in Oregon
On June 30, 2022, Emerald Ash Borer was discovered in Forest Grove, Oregon, marking the first confirmation of the invasive pest on the West Coast. The Tree Team posted an article about this news here, “Ash-Tree Killing Insect Now in Forest Grove.”
This pest has proven deadly to all ash species in North America and Europe, including the native Oregon ash (Fraxinus latifolia). In Oregon, the establishment of Emerald Ash Borer could devastate whole habitat types that are dominated by Oregon ash, such as ash swales and sensitive riparian zones. It could also reduce urban forest cover. In Portland, almost 4% of all street trees are ash - some 9,700. These could all be killed within a few years unless treated.
More information can be found - https://extension.oregonstate.edu/collection/emerald-ash-borer-resources.
Raywood ash make up about 15% of all median trees in the Ainsworth Linear Arboretum, or about one in eight trees. Unless treated, these are likely to be killed by Emerald Ash Borer in the future.