If you have an ash tree in your yard, this is the post to read carefully. The emerald ash borer — a small, metallic-green beetle from Asia — has killed hundreds of millions of ash trees across the Midwest, and the southwest Chicago suburbs have been hit hard. Entire streets in Orland Park, Tinley Park, and surrounding towns have lost their ash canopy over the past decade.
Here’s how to tell if your tree is affected, and what your options are.
How to Spot an Infestation
Emerald ash borer larvae tunnel under the bark, cutting off the tree’s ability to move water and nutrients. The damage shows up in stages. Look for:
- Canopy dieback starting at the top. Thinning leaves in the upper crown are usually the first visible sign. A healthy ash has a full, even canopy — a thinning top is a red flag.
- D-shaped exit holes. When adult beetles emerge, they chew distinctive D-shaped holes about 1/8 inch wide in the bark. This is the clearest confirmation of emerald ash borer.
- Bark splitting and woodpecker damage. As larvae feed underneath, bark cracks and splits. Woodpeckers strip off outer bark hunting larvae, leaving pale, flecked patches — heavy woodpecker activity on an ash is a strong indicator.
- Suckers and water sprouts. A stressed ash pushes out shoots from the trunk base and along the trunk. Lots of suckers on an ash usually means the tree is in serious trouble.
- Leafy decline over 2–4 years. Infested trees typically decline over a few seasons, then die. Once more than half the canopy is gone, the tree generally can’t be saved.
If you see several of these signs together, assume emerald ash borer until proven otherwise.
Treatment vs. Removal: What to Consider
There are really only two paths, and the right one depends on the tree’s condition.
Treatment (systemic insecticide, usually trunk injection or soil application) can protect a healthy ash or one in the very early stages of infestation. But be realistic about it: treatment isn’t one-and-done — it needs reapplication every one to two years for the life of the tree, it costs money each cycle, and it only makes sense for a valuable tree that’s still mostly healthy. Treating a tree that’s already half-dead is throwing money away.
Removal is the right call for ash trees with advanced dieback, structural damage, or bark falling off in sheets. And here’s the part that matters most: dead ash trees are genuinely dangerous. Dead ash wood becomes brittle fast — far faster than dead oak or maple. Dead ash drop limbs without warning and can fail at the trunk. A dead ash near your house, driveway, sidewalk, or anywhere people walk should be treated as a priority removal, not a “someday” project.
If you’re unsure which category your tree falls into, an in-person look during an estimate is the usual way to get a straight answer.
Don’t Move Firewood
Emerald ash borer spreads fastest the human way: in firewood. Moving infested wood to a campground, a new property, or a friend’s house plants the beetle in a new area. Illinois has had firewood quarantines in affected counties for years. The rule is simple: burn firewood where you cut it, and never transport ash wood out of the area.
What to Plant Instead
When an ash comes down, replant with diversity in mind — the reason the borer was so devastating is that entire neighborhoods were planted with a single species. Good replacements for the southwest suburbs include oaks (white, red, bur), hackberry, Kentucky coffeetree, ginkgo (male), and disease-resistant elm varieties. A mix of species on your property means no single pest can ever do this again.
Suspect Emerald Ash Borer? Don’t Wait
Ash decline doesn’t reverse on its own, and dead ash only get more hazardous with time. If your ash is thinning at the top, showing D-shaped holes, or shedding bark, get it assessed now.
Call The Best Tree Guys at (708) 665-4874 or request a free estimate through the online quote form. Serving Orland Park, Tinley Park, Homer Glen, Mokena, Frankfort, and the surrounding southwest Chicago suburbs.