Hello!

I would like to start with determining whether it is an ash tree or not. I cannot tell from the photos if the stems with the leaflets are arranged in an opposite or alternate orientation. I have attached a diagram, could you please check what the arrangement is? I can see from the photo that the leaflets are opposite.

Thank you,

Leo Sherry

OSU Extension Master Gardener Volunteer

Hello!

Thank you for your response about the leaf arrangement, it was very helpful. Based on the arrangement, it its likely an ash tree or an elderberry tree. Elderberries are usually shrubbier, so ash is more likely. They also have obvious fruit. Black walnut and English walnut trees have alternate stems. Do you remember ever seen samaras on the tree? Recognizing ash trees in Oregon, Washington and Northern California | OSU Extension Service (oregonstate.edu) is very helpful for ash tree identification.

There are a several characteristic signs of emerald ash borer.

1. D shaped exit holes. The photo of the holes that was sent looks like they are circular or oval. I think that the holes are from a woodpecker that is after insects or sap. If they are in a line, that can be a good indicator of woodpecker (sapsucker in particular) damage.

2. S shaped tunnels. The tunnels you showed don't quite look S shaped, but the branch may be too small to tell for sure. The tunnels also look wider than photos I have seen of emerald ash borer damage.

3. Splits in the bark on the tree. I see some vertical lines near the bottom of the trunk, but I can't tell if they are splits for sure.

4. Significant crown dieback in the top third of the tree.

5. Sucker shoots at the base of the trunk.

6. Woodpecker damage that gives a mottled look to the bark. I do not see this evident in the photos.

The adults are not visible right now, they are only active June-July.

I don't think there is enough evidence to indicate emerald ash borer, but please verify the presence or absence of the common signs. Sightings or suspected sightings can be reported here: Report an Invader (oregoninvasiveshotline.org).

There are many other wood boring insects that could make tunnels like you saw. It's also possible that the damage was done after the branch left the tree. None of the patterns I saw matched the pattern of tunnels you have, but there are many possible culprits.

I found these resources the most helpful about emerald ash borer:

Emerald Ash Borer - A New Invasive Pest | OSU Extension Service (oregonstate.edu)

Oregon Forest Pest Detector Pest Watch—Emerald ash borer (EAB) | OSU Extension Service (oregonstate.edu)

fact-sheet-emerald-ash-borer.pdf (oregon.gov)

I hope this helps!

Regards,

Leo Sherry

OSU Extension Master Gardener Volunteer