Oregon has renewed a quarantine of ash and white fringe tree materials from Washington County, on the western outskirts of Portland, to control the spread of the emerald ash borer.

The most recent quarantine replaces one first adopted in June 2022, when the EAB was first detected in Forest Grove, Ore. It exempts olive trees and is set to expire on Nov. 11.

The quarantine restricts the movement of several tree materials, including but not limited to logs, green lumber, nursery stock, scion wood, bud wood, chips larger than 1 inch by 1 inch, mulch, stumps, roots, branches, and firewood of hardwood species, according to the Oregon Department of Agriculture.

Researchers consider the half-inch green, shiny beetle North America’s most destructive forest pest, killing hundreds of millions of ash trees nationwide, the ODA explains. So far, Oregon has only detected EAB within the city limits of Forest Grove.

EAB is native to Asia. Its larvae burrow into the bark of ash trees, causing canopy dieback and, ultimately, tree death. The beetle is often challenging to detect, especially in newly-infested trees. Signs of infestation include thinning and yellowing leaves, bark splitting, D-shaped holes in the tree bark, and basal shoots.

ODA is establishing several processing and disposal resources to limit the movement of ash and white fringe tree materials within the quarantine area.

For more information on the emerald ash borer, click here. Information on the temporary quarantine is here.

Source: Oregon Department of Agriculture