Bark girding?

Asked September 22, 2019, 4:34 PM EDT

Hello, We have European Hornets girding branches on our lilac bushes near our house. We watched them fly to the woods behind our yard so we assume they are building a nest. While trying to track them I noticed the odd markings on the bark of this hardwood tree. The next day there were more markings. The next day, more. Can you identify these markings and are the hornets making these marks by girding?

Frederick County Maryland wildlife invasive trees eab blonding of bark not european hornet damage woodpecker on ash

3 Responses

European hornets do strip bark from lilacs this time of year, but they didn't damage this tree. They also would have built their nests long ago.
Here is our page on them:

You didn't say, but we would guess that this tree might be an Ash which has been killed (if not dead yet it soon will be) by Emerald Ash Borer. As the trees die, woodpeckers are attracted to the borers within the tree. The stripped bark is what we refer to as 'blonding' and commonly appears as woodpeckers find their prey.
These trees decline very quickly and can become a fall hazard. If it is in a place where it would threaten people or property, have it removed sooner rather than later.
More about Emerald Ash Borer here:


Thank you Christine. Yes, this is a MD Ash tree and I agree that it has shown signs of the Emerald Ash Borer. Our woods is filled with ature MD Ash trees. What can we do about the pest? I am concerned that our entire woods could be wiped out. We have several different types of woodpeckers, maybe more now that EAB has moved in. Do the European Hornets eat EAB? Do woodpeckers eat E.Hornets? I can imagine that treating our woods could be expensive and are the chemicals toxic?

Please read through the information we gave you above about emerald ash borer. They kill all ash. Treatment is expensive and will have to continue forever. We only recommend it for historical or specimen trees. EAB is a foreign invasive insect that is wreaking an environmental catastrophe all over the U.S.

If you have a woods that is primarily ash, expect a lot of dead trees. Dead trees are highly beneficial to wildlife as a food source and for living habitat, so they do not need to be removed unless they may fall on a building, etc.

As ash die, they open up the woods canopy to sunlight. More invasive plants may move in. You may have to remove these as they appear. Prompt removal will save you a LOT of work in the long sun.

Meanwhile, you can start to regenerate your woods by planting new saplings of native trees. Fence these with wire or plastic sleeves when they are young to protect from deer feeding and rubbing.

There is no connection with European borers. The woodpeckers are seeking the EAB larvae.