Emerald Ash Borer in Tennessee: What Chattanooga Homeowners Should Know

Emerald ash borer (EAB) is a small metallic-green beetle, native to Asia, that has killed tens of millions of ash trees across North America since it was first detected in 2002. Tennessee is squarely inside the infestation zone, and Chattanooga homeowners with ash trees on their property need to know what's happening — because by the time the damage is obvious, it's usually too late to save the tree.

Identifying ash trees in your yard

Before you can worry about EAB, you need to know whether you actually have ash. Key identifiers:

• Opposite branching — branches and buds grow directly across from each other (one of only a few common landscape trees that does this).
• Compound leaves — each “leaf” is actually 5 to 11 leaflets along a central stem.
• Diamond-pattern bark on mature trees.
• Canoe-paddle-shaped winged seeds hanging in clusters in late summer.

Signs of an EAB infestation

The beetle larvae feed under the bark, cutting off the tree's ability to move water and nutrients. Symptoms include:

• Canopy thinning — usually starts at the top of the tree.
• Epicormic shoots — new sprouts coming directly out of the trunk or large limbs, as the tree tries to compensate.
• D-shaped exit holes in the bark, about 1/8 inch wide.
• S-shaped galleries under the bark when a piece is peeled back.
• Bark splitting over feeding galleries.
• Increased woodpecker activity — woodpeckers love EAB larvae and will strip bark to get at them.

Treatment options

EAB is treatable, but timing matters. The decision usually comes down to four questions:

1. How much canopy is the tree still carrying? Treatment is most successful on trees with less than ~30% canopy loss. Heavily declined trees usually can't recover.
2. How important is the tree? A mature ash shading the south side of your house is worth more than a young volunteer ash on the back fence line.
3. What's the trunk size? Treatment is dosed by trunk diameter, so larger trees cost more per application.
4. Are you committed to ongoing treatment? Most treatments need to be repeated every 2–3 years for the rest of the tree's life.

Common treatments include systemic insecticide trunk injections and soil-applied insecticides, both performed by qualified applicators. We can talk through whether your specific tree is a good treatment candidate.

When removal is the right call

If an ash is already in significant decline — bark falling off, half the canopy dead, woodpecker damage extensive — treatment will not bring it back. At that point removal is about safety: dead ash trees become brittle quickly, and they're notoriously dangerous to climb or remove once they reach that stage.

Planting after ash removal

If you're removing an ash, consider replacing it with a diverse mix — not another ash. Good Chattanooga-area alternatives include oaks, tulip poplar (where space allows), eastern redbud, dogwood, and serviceberry.