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Dead or Dying Ash Trees in East Tennessee: Emerald Ash Borer, Warning Signs and Removal Safety
Emerald ash borer was first found in Tennessee in Knox County. Here's how to tell if your ash is affected, why dead ash shouldn't be left standing for long, and what the firewood rules say.
This is general information, not a diagnosis. If you aren't sure what's wrong with a tree, contact your UT Extension county office or the Tennessee Division of Forestry (615-837-5432). Last reviewed October 2026.
What is emerald ash borer?
- Emerald ash borer (EAB) is an invasive beetle from Asia, first found in the U.S. in Michigan in 2002. It attacks only ash trees.
- It was first found in Tennessee in July 2010, at a truck stop along I-40 in Knox County. The state now lists 66 counties with confirmed infestations, and USDA reports EAB in 38 states plus the District of Columbia.
- Larvae tunnel under the bark and cut off the tree's flow of water and nutrients. The Tennessee Department of Agriculture says small trees may die within 1–2 years of infestation and large trees within 3–4.
- It spreads mainly when people move nursery stock, firewood, unprocessed logs and other ash products.
Source: Protect Tennessee Forests (TDA), Emerald Ash Borer
Source: USDA Forest Service, A Forest Death in Three Acts (Knight, Flower & Nelson, 2019) (PDF)
Source: USDA APHIS, Emerald Ash Borer
Source: TN Dept. of Agriculture, Emerald Ash Borer Awareness Week (May 2021)
Is it an ash tree?
- Leaves and branches grow in opposite pairs. Each leaf is compound, with 5–9 leaflets (usually 7 or 9).
- Bark has a pattern of interlacing ridges.
Signs an ash is dying
- Thinning and dieback at the top. Dieback of the upper canopy is one of the first signs. Branches die first, then the whole tree.
- D-shaped exit holes about 1/8 inch wide in the bark.
- S-shaped tunnels under loose or split bark.
- Sprouts from the base or trunk, often called epicormic shoots.
- Woodpecker damage. Heavy feeding can strip outer bark and leave light patches, which is known as "blonding."
- Vertical splits in the bark.
- Decline often doesn't show until a tree has been infested for 1–3 years. Adult beetles are metallic green, about 1/2 inch long, and are out from roughly June through August.
Source: TN Dept. of Agriculture, Emerald Ash Borer Awareness Week (May 2021)
Source: Protect Tennessee Forests (TDA), Emerald Ash Borer
Source: UT Extension Sullivan County, Emerald Ash Borer and Thousand Cankers Disease (PDF)
Source: USDA APHIS, Emerald Ash Borer
Treat it or take it down?
- The state says ash trees with more than 50% canopy thinning typically can't be effectively treated with insecticides.
- Healthy ash can be protected. Certified arborists can be hired to treat healthy trees, and the Department of Agriculture says homeowners can treat smaller healthy trees with over-the-counter insecticides labeled specifically for the borer.
- Either way there's a cost, whether you treat a live tree or remove a dead one. If you replace an ash, the state suggests planting a different native species.
Source: Protect Tennessee Forests (TDA), Emerald Ash Borer
Source: TN Dept. of Agriculture, Emerald Ash Borer Awareness Week (May 2021)
Source: UT Extension Sullivan County, Emerald Ash Borer and Thousand Cankers Disease (PDF)
Why dead ash is risky to remove
- Dead ash turns brittle fast. USDA Forest Service researchers write that dead ash wood rapidly becomes brittle, and limbs and whole trees fall.
- Decay fungi speed it up. University of Minnesota research found aggressive wood-decay fungi in EAB galleries. Untreated ash lose structural integrity quickly and become subject to branch, limb and trunk failure.
- Branches can snap with little warning. New Jersey's Department of Agriculture warns that little to no stress can make infested branches snap or shatter, including vibration from a chainsaw, and that workers should never climb a symptomatic ash.
- Waiting can change how it's removed. University of Maryland Extension says tree companies won't climb ash that has been dead more than six months, and a crane may be needed, which raises the cost. They recommend having dead ash near homes removed promptly.
- For what affects the price of a removal, see the cost guide. If an ash comes down in a storm, see emergency tree removal.
Source: USDA Forest Service, A Forest Death in Three Acts (Knight, Flower & Nelson, 2019) (PDF)
Source: NJ Dept. of Agriculture, Tree Care Worker Risk Alert: Infested Ash Trees (PDF)
Source: University of Maryland Extension, Emerald Ash Borer
Source: University of Maryland Extension, How Do You Decide When to Remove a Tree?
Firewood: what the rules say now
- No EAB quarantine in Tennessee. State and federal EAB quarantines were lifted in 2021.
- Firewood coming into Tennessee is regulated. Since September 12, 2021, firewood from outside the state (other than from counties bordering Tennessee) must be heat treated (160°F for 75 minutes) and labeled with a treatment stamp, the manufacturer's name, the quantity and the county and state of origin. Questions go to Plant.certification@tn.gov or 615-837-5137.
- Inside Tennessee, the official advice is "Don't move firewood." EAB can be carried from other areas in the state too. Buy it where you'll burn it, or use certified heat-treated firewood.
Source: TN Dept. of Agriculture, Quarantines
Source: Protect Tennessee Forests (TDA), Emerald Ash Borer
Source: USDA APHIS, Emerald Ash Borer
Source: TN Dept. of Agriculture, Tennessee's Firewood Quarantine in plain language (2026, PDF)
Hiring someone for a dead ash
- For large dying or dead ash, the Department of Agriculture advises hiring an ISA Certified Arborist. If one isn't available, make sure the company has liability and workers' compensation insurance.
- Get several written estimates that spell out wood disposal and cleanup, and ask for proof of insurance and references.
- Removing the stump? Notify utilities through 811 at least three business days before digging or grinding. See stump grinding.
- Trees on city property or in the right-of-way aren't yours to remove. In Knoxville they need the Urban Forester's written approval. Check the permit guide for your city.
- Not sure it's EAB? Contact your county Extension agent, a forester, or the Division of Forestry at 615-837-5432.
Source: TN Dept. of Agriculture, Emerald Ash Borer Awareness Week (May 2021)
Source: University of Maryland Extension, Emerald Ash Borer
Source: KUB, Call 811
Source: Knoxville City Code, Chapter 14 (Trees), City-hosted copy
Have a dead or declining ash?
Send the short form and mention that it's an ash, how close it is to the house, driveway or lines, and roughly how long it has looked dead. A photo of the canopy helps.
Related: emergency tree removal · tree removal cost guide · permit guide · stump grinding
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