Become An Ash Tree Ally

Join the Emerald Ash Borer Community Science Project

With the recent arrival of the Emerald Ash Borer (EAB) on the West Coast, the City of Mercer Island is proactively working to identify the locations of all potentially vulnerable ash (Fraxinus) trees. Members of the community can assist with this effort by gathering information that will help to create a pest management plan that mitigates potential impacts of EAB, a destructive invasive beetle species that can kill many types of ash trees.

Participate in this beneficial community science project by following these steps:

• Learn to identify ash species and start looking for them in your neighborhood or a park
• Log ash tree locations in the iNaturalist Ash Tree Inventory Project, a free geolocated app that can help you identify species
• Examine the ash trees that are located for signs of EAB
• Report EAB sightings to Urban.Forestry@MercerIsland.gov and to the Washington Invasive Species Council by downloading an app (link to apps on website)

Scientists first detected EAB (Agrilus planipennis Fairmaire) in North America in 2002, near Detroit, Michigan. Since then, EAB has infected trees in 37 states and six Canadian provinces, including Oregon in 2022 and British Columbia in 2024. Experts believe EAB will soon spread to our area.

During its larval stage, EAB consumes the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients. After losing the leaves on their top branches, infected trees eventually die.

With no natural predators in North America, it has caused extensive environmental and financial damage, resulting in the loss of millions of ash trees and hundreds of millions of dollars in damage.