Ash trees under beetle threat

It’s not good news, but it’s important to know: The Emerald Ash Borer (EAB), a destructive insect that kills ash trees, is now in Oregon and here to stay.

The invasive beetle has been confirmed in five Oregon counties, including Multnomah County. It attacks ash tree species (Fraxinus spp.), including native Oregon ash, and infested trees usually die within three to seven years.

“Our ash trees are under threat, and community awareness is the most important thing right now,” said Jeff Lesh, Environmental Specialist for the City of Gresham.

Infested ash trees can quickly become brittle and unstable, creating potential safety risks for people and property.

Above: Jeff Lesh, Environmental Specialist for the City of Gresham, inspects ash trees at the Gresham Post Office for signs of infestation.

Help slow the spread

While EAB can’t be eradicated, residents can help slow its spread and reduce its impact.

• Don’t move firewood. Buy it where you burn it.
• Don’t plant ash trees. 
• Avoid pruning ash trees during summer months when the insects are most active. 
• Learn to identify ash trees and signs of infestation. 
• Report sightings through the Oregon Invasive Species Hotline website.

Watch for signs of stress, such as thinning leaves and dead branches in the canopy. The beetles themselves are small, metallic green and often hard to spot because they spend most of their time high in the tree.

“If you know about this insect and you have an ash tree, you can take steps to protect your tree,” Lesh said. “A tree care professional can help assess your tree and determine whether treatment or removal and replacement is the best option.”

Learn more about the emerald ash borer or call 503-618-2525.