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Emerald Ash Borer Peeling Bark Trail on Ash Tree

Don’t procrastinate:

Early detection is key to managing the threat posed by the emerald ash borer (EAB), so don’t wait to identify whether you have an ash tree. And if you do have an ash, visually inspect that tree regularly. Also, subscribe to email updates on the EAB in Denver in the footer below.

Develop a plan:

So you have an ash tree. Now what? The short answer is you have two options: treatment or replacement. The one option you shouldn’t consider, however, is treating or replacing your ash tree yourself if you’re not a licensed tree professional. Contact a tree expert to help execute your EAB defense plan.

Know what to look for:

How can you tell if your ash is infested with EAB? Look for D-shaped exit holes, wavy trail lines, bark falling off the tree and Northern Flickers (type of woodpecker), among other things, or view a full photo gallery of what you should be looking for.

Who ya gonna call?

If ash trees show signs or symptoms of EAB infestation, contact the Office of the City Forester at or (720) 913-0651.

Have a smart mouth:

Talk to your neighbors, friends and co-workers about the EAB and what they should look for on their ash trees.

Buy local, burn local:

Don’t move any firewood, and you won’t move any borers. It’s the rallying cry in the fight against the EAB if ever there was one. People unknowingly contribute to the spread of the EAB when they transport firewood or other products from ash trees, as EAB larvae stealthily survive and travel hidden under the bark. If an ash tree absolutely has to be moved, always remember the wood needs to be chipped smaller than one inch.

Start planting now:

Obey the old Chinese proverb: “The best time to plant a tree is 20 years ago. The second best time is now.” Truly, if you decide to replace your ash tree with one of these City Forester-approved trees – some of which you might even be able to get for free – you’ll help maintain the long-term stability of our urban canopy.

Image courtesy Colorado State Forest Service