Officials from Oregon’s Forestry Department said Monday that an invasive insect responsible for decimating ash trees in North America and Europe had been discovered west of Portland.
According to the Oregon Department of Forestry, the iridescent green Emerald Ash Borer (EAB), is the most destructive pest of North America. It has been found in 34 states before it was discovered at Forest Grove on June 30, 2012.
After traveling through 35 states, the Emerald Ash Borer has finally made its way to Oregon. It is harmless to animals and people, but can kill ash trees. It was seen in Forest Grove on June 30, 2018. See photos and learn more at https://t.co/nOEzOwVFxK pic.twitter.com/88pdFeujah
Officials claim it is the first time the insect has been discovered on the West Coast. It is believed that the beetle arrived in America from Asia, Canada around 20 years ago.
In some places in North America, the insects have decimated up to 99% ash trees. For example, Connecticut’s ash tree population has been decimated by years of beetle infestations.
Dominic Maze, a City of Portland invasive species biologist, discovered the emerald-ash borer. State officials stated that he was standing outside Forest Grove’s summer camp waiting to pick up his children, when he saw several ash trees with D-shaped exit points in their bark.
The holes were a sign that the emerald-ash borer was present and he spotted the beetles. He called the Oregon Department of Forestry, and an entomologist as well as two other specialists in invasive species confirmed that the invasion had occurred.
Wyatt Williams of the Oregon Department of Forestry, a specialist in invasive species, stated that “it’s an ecologically important tree as it shade water, keeping it cooler to fish.” The roots help to stabilize streambanks and reduce erosion. The leaves and seeds are eaten by many animals, birds, and insects. It will have a significant impact on these ecosystems if it is lost.”
Within 48 hours of discovering the infestation, the trees in Forest Grove were removed and chipped.
Williams stated that EAB was the most destructive and costly forest pest to infiltrate North America since it was discovered in Detroit, Michigan in 2002.
The Emerald Ash Borer Readiness and Response Plan For Oregon was finalized by the Oregon Invasive Species Council in 2021 to help Oregon with its response.
To preserve Oregon’s genetic diversity, the Oregon Department of Forestry already collected seeds from Oregon Ash trees. The seeds will be tested to determine if they are resistant to ash borer infestations. If so, researchers may be able breed resistance into local strains to replant them.
Officials said that Oregonians and cities should think about removing ash trees in poor health, or in areas too small for them. They also need to remove ash trees from street tree lists. Portland already has removed it from the trees it plants.
Scott Altenhoff is the manager of the Urban and Community Forestry Assistance program at Oregon Department of Forestry. “Starting to steadily substitute ash will spread out costs and impacts better than waiting until there is a huge dieoff,” he said. “Fortunately, there are other tree species available, such as the Oregon white oak, Chinese pistache and incense cedar, which might be more resistant to heat and drought than ash.
The Oregon Department of Forestry states that ash borer is a native of eastern Asia. This includes far eastern Russia and China, Mongolia, Japan (Taiwan), Taiwan, and the Korean Peninsula. According to the department, the pest was probably introduced to the Great Lakes region by international shipping of infested wood material.
