Ash trees in peril as Emerald Ash Borers are coming

An Ash tree in Old Town. Photo by author

I attended the city’s Preparing for the Emerald Ash Borer workshop last weekend and now I look at my own Ash tree differently today.

The Emerald Ash Borer (EAB) is an invasive insect that infests and kills all varieties of Ash trees. The workshop covered Ash tree identification, signs and symptoms of EAB, management strategies, and tree species alternatives for replacing Ash. Most of this material--and there is a lot--is also available on the city’s website.

Bottom line, the news is not good. The EAB is expected to arrive in Lake Oswego soon and cannot be eradicated. It has been detected in King City and other nearby towns. Unlike pests like the Japanese Beetle that can be trapped (you might have seen a few traps in Old Town), there is no cure or predator of the penny-sized pest and its larva. Infested trees die within 3 to 7 years.

Lake Oswego's first Urban Forester, Courtney Wilson and Kaleb Simpson, Natural Resource & Stewardship Coordinator, led the workshop. The city has made an inventory of Ash trees in key public areas like parks and roads. The city has been treating some Ash trees using special insecticides injected directly into the tree. This should save the tree. However, 80% of Lake Oswego’s tree canopy is on private lands. Homeowners can also treat Ash trees, but it is a commitment. These injections cost hundreds of dollars and need to be done every two-to-three years since you are changing the structure of the tree.

There’s plenty of more information from the city and Oregon’s own EAB site and what you can do. I would investigate especially if you have ash trees on your property. This way you can identify if the tree is--or when?-- invaded by EAB.

As you know Lake Oswego take trees seriously and you have a chance to learn from the city experts with their next free tree workshop on Tree Species Identification, which will be at George Rogers Park on August 8 (register here).