Confirm the species before anything else: opposite branching, compound leaves with five to eleven leaflets, and diamond-patterned ridges on mature bark. Very few Vermont trees combine opposite with compound — maple is opposite but simple-leaved, walnut is compound but alternate. Then read where the tree sits in a fixed sequence. Thinning starts in the upper canopy, because the insect works from the top down. Epicormic sprouts appear on the trunk as the tree compensates. Small D-shaped exit holes follow, then pale blonding where woodpeckers have flaked bark away chasing larvae, which usually means the tree is already heavily infested. A tree with a full canopy that you value is a treatment decision, and treatment is a repeating commitment rather than a cure. A tree already thinning is a removal decision, and deferring it costs money: ash goes brittle within a couple of years of death and stops being climbable.
Identify the species, then read the stage
- 2. Look for canopy thinning, epicormic shoots, bark flecking and galleries, but do not rely on one symptom alone.
- 3. Discuss treatment while the tree still has enough healthy canopy and value to justify recurring care.
- 4. Plan removal before advanced decline makes already brittle ash more difficult to work around.
- 5. Follow current Vermont Invasives guidance for reporting and moving ash material.
Identifying ash, and reading the symptoms in order
Confirm the species first, then read where the tree is in the sequence. Symptoms appear in a fixed order and the tree is usually infested for a couple of seasons before the first one shows.
| Stage | What is visible | What it means |
|---|---|---|
| Identification | Opposite branching, compound leaves, diamond bark | It is an ash — very few Vermont trees combine opposite and compound |
| 1. Upper canopy thinning | Bare twigs at the top, worsening yearly | Infested for at least a season or two already |
| 2. Epicormic sprouts | Shoots erupting from the trunk | The tree is compensating for lost canopy |
| 3. Exit holes | D-shaped, about an eighth of an inch | Adults have emerged; population is established |
| 4. Blonding | Pale patches where woodpeckers flaked the bark | Heavily infested; treatment is unlikely to succeed |
| 5. Dead | No leaf-out | Brittle within a couple of years; not climbable |
Check Vermont Invasives for current guidance before moving any ash material off the property it grew on.
What an ash assessment needs to know
The decision turns on how much canopy is left and on what sits beneath the tree, so those two are worth establishing before anything else.
- Whether you are confident it is an ash, and why
- Roughly what fraction of the canopy still leafs out
- Any bark flecking, sprouts on the trunk, or exit holes
- What is underneath: house, drive, road, or nothing
- Whether you would fund a repeating treatment
Why the guidance has to be checked, not remembered
Treatment prospects depend on the tree's actual condition, and the guidance on moving ash material changes as the infestation spreads. Confirm the current position at the time you decide.
12 questions this raises
How do I confirm a tree is an ash before I do anything?+
Three features together. Branches and leaves arranged opposite each other rather than alternating; each leaf compound with five to eleven leaflets on a single stalk; and mature bark in a distinct diamond-patterned ridge. Very few Vermont trees combine opposite with compound — maple is opposite but simple-leaved, black walnut is compound but alternate. Opposite plus compound and not a maple is very likely ash.
What are the symptoms in the order they appear?+
Thinning and dieback in the upper canopy first, because the insect starts high. Then epicormic sprouts on the trunk as the tree tries to compensate. Then D-shaped exit holes about an eighth of an inch across. Then blonding — pale patches where woodpeckers have flaked the bark away chasing larvae — which is often the most visible sign from a distance and means the tree is already heavily infested.
How long has the insect usually been in the tree before I notice?+
Typically a couple of seasons. That is why a tree that 'suddenly' looks bad has in fact been infested for a while, and it is the reason decline seems to accelerate: you are seeing the later part of a process that started invisibly. Treat a visibly symptomatic ash as being on a short clock rather than at the beginning of one.
Is treatment actually effective?+
It can be, on the right tree started at the right time — a healthy, structurally sound ash with most of its canopy intact, in a position where losing it would matter. Started after significant canopy loss it is much less likely to succeed. The important part to be clear-eyed about is that it is a repeating commitment for the life of the tree, not a single application.
How do I decide between treating and removing?+
Ask three questions. Is the tree worth keeping on its own merits — good structure, good position, real value to the property? Is enough canopy still there for treatment to work? And are you willing to fund a recurring treatment indefinitely? Three yeses point to treatment. Any no points to planned removal on your own schedule, which is much cheaper than an emergency one later.
Why is a dead ash harder to remove than other dead trees?+
Because ash becomes brittle far faster than most species once it dies. Within a couple of years the wood loses the toughness a climber depends on, branches snap without warning, and the trunk can shatter rather than hinge when cut. Crews frequently refuse to climb a dead ash and use a bucket or a crane instead — which costs more. That is the practical reason not to defer.
Can I move the wood?+
Check the current Vermont guidance before moving any of it, and default to not. Firewood and untreated ash material are the main way the insect reaches new areas, which is exactly what Vermont's guidance on ash material movement addresses. Using the wood on the property where it grew, chipping it small, or buying local heat-treated firewood at your destination are the safe options.
What about the ash trees on my woodlot rather than near the house?+
Sort by what is underneath them. Ash near a house, a driveway, a road frontage or an outbuilding needs a decision now. Ash out in the woods with nothing beneath it can be left to fall on its own schedule — it is doing no harm standing there, and removing it costs money for no risk reduction.
Should I remove a healthy ash pre-emptively?+
Only if you have decided you would not fund treatment. If that is the answer, doing it now — while the wood is sound, a climber can work it, and you can pick the date — is materially cheaper and safer than doing it in three years as a bucket job. If you might treat it, do not remove a healthy tree on the strength of what might happen.
What should replace a removed ash?+
Anything but ash, and preferably something different from what your neighbours have. Dutch elm disease taught it once and this outbreak is teaching it again: a street or a garden planted to one species loses the lot at once. Choose for the site — root volume, drainage, salt exposure near a road, the space the mature crown needs — rather than for fashion.
Are all of Vermont's ash trees going to die?+
Untreated ash is expected to be lost over time, which is what has happened wherever this insect has taken hold. That is why municipalities across this region have been inventorying ash, removing declining trees on a planned schedule and replanting with mixed species rather than waiting. The same logic applies to a private owner at a smaller scale.
Where do I report or check current guidance?+
Vermont Invasives is the state's public resource for emerald ash borer, including the current position on moving ash material and on where the insect has been confirmed. Because that guidance changes, check it at the time you are making the decision rather than relying on what was true a year ago — including anything on this page.
Vermont invasive-species resources
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