A Pest That Changed Michigan's Landscape
Since it was first detected in Southeast Michigan in 2002, the emerald ash borer (EAB) has killed tens of millions of ash trees across the state. Grand Rapids and the surrounding communities have not been spared. Drive through almost any neighborhood in Forest Hills, Kentwood, or East Grand Rapids and you'll see the evidence — standing dead ash trees, fresh stumps where they used to be, and gaps in the canopy that weren't there a decade ago.
At B's Trees, we've removed and treated our share of EAB-damaged ash trees across the area. This article covers what every homeowner with an ash tree on their property should know — how to identify the problem, what the treatment options look like, and how to decide between saving the tree and taking it down.
How to Identify an Ash Tree
Before worrying about EAB, it helps to know whether you actually have ash trees on your property. Ash trees are extremely common in West Michigan — they were planted heavily as street and yard trees throughout the 1970s, '80s, and '90s.
Key identification features:
- Compound leaves with 5–9 leaflets arranged opposite each other along a central stem
- Opposite branching pattern — branches emerge in pairs directly across from each other
- Diamond-patterned bark on mature trees, with interlocking ridges that form a distinctive diamond or braided pattern
- Winged seeds (samaras) that hang in clusters — similar to maple seeds but in bunches rather than pairs
If you're not sure, our team can identify the species during a free property assessment. It takes about 30 seconds for a trained arborist to confirm.
Signs of Emerald Ash Borer Infestation
EAB larvae feed on the inner bark of ash trees, disrupting the flow of water and nutrients. The damage happens under the bark where you can't see it — but the tree eventually shows external symptoms. Here's what to watch for:
Early Signs
- Canopy thinning — the crown of the tree starts to look sparse, especially at the top. Leaves may be smaller than normal or lighter in color.
- Epicormic sprouting — new shoots growing directly from the trunk or large branches. This is the tree's stress response — it's trying to produce new foliage closer to the root system because the upper canopy is failing.
- Bark splitting — vertical cracks in the bark that may reveal S-shaped larval galleries underneath.
Advanced Signs
- D-shaped exit holes — small, distinctly D-shaped holes about 1/8 inch wide in the bark. These are left by adult beetles emerging from the tree. This is the most definitive visual sign of EAB.
- Woodpecker damage — heavy woodpecker activity on an ash tree often means they're feeding on EAB larvae under the bark. If the bark looks like it's been stripped or "blonded" in patches, woodpeckers have been working.
- Major dieback — more than 50% of the canopy is dead or dying. At this stage, the tree's vascular system has been severely compromised.
Treatment Options
The good news is that EAB-infested ash trees can often be saved — if the treatment starts early enough. The window matters. Once a tree has lost more than about 50% of its canopy, treatment becomes significantly less likely to succeed and removal is usually the more practical path.
Trunk Injection (Emamectin Benzoate)
This is the treatment method with the strongest track record. A systemic insecticide is injected directly into the trunk, where it's distributed through the tree's vascular system. It's effective for two to three years per application, depending on the product and tree size.
Key considerations:
- Most effective when applied during the treatment window — generally mid-May through June in Michigan, when the tree is actively transpiring
- Must be applied by a licensed applicator
- The tree needs to have enough healthy canopy remaining to distribute the product
- Ongoing commitment — treatment needs to be repeated every 2–3 years for the life of the tree
Soil Drench (Imidacloprid)
A systemic insecticide applied to the soil around the base of the tree. It's absorbed through the root system. This method is less invasive than trunk injection but tends to be less effective on larger trees (generally those over about 15 inches in diameter). It's sometimes used as a preventive measure on smaller, healthy ash trees.
When Removal Is the Right Call
Not every ash tree can — or should — be saved. We recommend considering removal when:
- More than 50% of the canopy is dead or severely thinned
- The trunk shows extensive woodpecker damage and bark loss
- The tree is in a location where failure could damage a home, vehicle, or high-traffic area
- The ongoing cost of treatment doesn't make sense relative to the tree's condition and value
- The tree was already declining from other factors (root damage, prior storm damage, poor structure)
Dead and declining ash trees become increasingly brittle over time. The wood dries out quickly once the tree dies, and branches can snap without warning. We strongly recommend not waiting too long on removal decisions — a dead ash that's been standing for two or more years is significantly more dangerous and more expensive to remove than one addressed promptly.
What We Recommend
If you have ash trees on your property in the Greater Grand Rapids area, here's our plant health care team's general approach:
- Get an assessment. We'll identify the species, evaluate the canopy condition, check for EAB signs, and give you an honest recommendation.
- Treat early if the tree is worth saving. Healthy ash trees in good locations with minimal canopy loss are strong candidates for treatment. The investment pays off over decades of continued shade, property value, and aesthetic benefit.
- Remove promptly if the tree is too far gone. Waiting only makes the job harder and riskier. We can also help with replanting recommendations — species that are well-adapted to West Michigan and not susceptible to EAB.
- Plan for the long term. Whether you treat or remove, think about your overall tree canopy. Diversifying the species on your property is the best protection against the next pest or disease that comes along.
EAB isn't going away. But with the right information and a proactive approach, we can help you make the best decision for your trees and your property. Reach out for a free assessment or call us at 616-947-4050.
Frequently Asked Questions
- How much does EAB treatment cost vs. tree removal?
- Both costs vary significantly depending on the tree's size, condition, and location. Treatment is an ongoing expense repeated every 2–3 years, while removal is a one-time cost. For a healthy ash tree in a good location, treatment is often the more economical long-term choice when you factor in the value the tree provides. We can walk through both options and the costs during a free assessment — call 616-947-4050 or request a quote online.
- Is it too late to treat my ash tree for EAB?
- It depends on how much canopy the tree has lost. Trees with less than roughly 50% canopy loss generally respond well to trunk injection treatment. Once a tree has lost more than half its canopy, treatment success drops significantly and removal is usually the more practical option. The best way to know is to have a certified arborist assess the tree in person.
- Are there ash tree varieties that are resistant to EAB?
- Research is ongoing, but currently no North American ash species has shown reliable resistance to EAB. Some Asian ash species have natural resistance because they co-evolved with the beetle. Researchers are working on developing resistant cultivars, but these aren't widely available yet. For now, treatment or removal remain the primary management options.
- Can EAB spread to other types of trees?
- No — EAB exclusively attacks ash trees (genus Fraxinus). It does not infest maples, oaks, elms, or any other species. If you're seeing similar symptoms on a non-ash tree, a different pest or disease is the cause. A certified arborist can help diagnose the issue.