unknown on May 15, 2024

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Description of specimen

Hi there,

I was working out at Willow Creek Preserve in Eugene, Oregon this week and noticed that there are clusters of Oregon ash trees that have top-canopy die off in a particular unit of our preserve. These trees also have new shoots sprouting from the base. I am attaching pictures of my observations. I inspected these trees further and did not see clear and frequents signs of wood boring insects, with the exception of boring holes in the cat faces of a handful of trees that were previous burned in a prescribed burn, however these were not ‘D’ shaped. Of course, I am concerned that this type of die off is one of the described signs of emerald ash borer and I am hoping you can provide further guidance on monitoring these trees or if someone would be willing to come and inspect the unit of concern. Having not observed any beetles, I’m curious how to delineate between canopy die off from stress and canopy die off from EAB.

I will say that I started my role as preserve steward in September and so I don’t have a long history with these areas.

My advance thanks for your response.

Best,
Sophie Linden

Commentary

Sophie, thanks for your report. What you describe is a common occurrence with Oregon ash. Canopy decline and canopy dieback is common. Usually we attribute this to changes in water table or another biotic reason. One issue is that Oregon ash hasn’t been studied as much as other Oregon tree species, so we are still learning about things that damage.

https://extension.oregonstate.edu/catalog/pub/em-9380-oregon-ash-insects-pathogens-tree-health

ODF has a monitoring guidance for EAB. I suggest continuing to look for canopy dieback. And then investigate individual trees for EAB exit holes and galleries under the bark. You have to cut a window in the bark to look for galleries.


https://www.oregon.gov/odf/forestbenefits/Documents/eab-monitoring-guidance.pdf

Wyatt Williams
May 16, 2024, 3:57 a.m.