Emerald Ash Borer in NJ: Save or Remove Your Ash Tree?

If you own an ash tree in Essex or Morris County, emerald ash borer (EAB) has almost certainly reached your neighborhood. A healthy-looking ash with early infestation can often be saved with trunk-injection treatment, but once more than roughly 30–50% of the canopy has died, removal is the safer and more cost-effective choice.

How do I know if I have an ash tree?

Correct identification matters, because EAB attacks only true ash (Fraxinus species) — white ash and green ash are the two most common in northern NJ. Look for these features together:

• Opposite branching — branches, buds and leaves grow directly across from each other, not staggered.
• Compound leaves with 5 to 9 leaflets on a single stem.
• Diamond-patterned bark on mature trunks — ridges form a tight, interlacing diamond texture.
• Canoe-paddle seeds (single-winged samaras) hanging in clusters on female trees.

Mountain ash and boxelder are frequently confused with true ash but are not hosts. If you are unsure, our team can confirm the species during a free visit.

What are the signs of emerald ash borer damage?

EAB larvae tunnel just under the bark, cutting off the tree’s ability to move water and nutrients. Damage starts high in the canopy and works down, so the earliest signs are easy to miss from the ground. Watch for:

• D-shaped exit holes — about 1/8 inch wide with one flat side, left when adult beetles emerge in late spring. This is the signature symptom.
• Canopy dieback starting at the top and outer branches, often 30–50% within the first couple of years.
• Bark splitting — vertical cracks revealing the S-shaped larval galleries winding beneath.
• Woodpecker flecking (“blonding”) — light-colored patches where woodpeckers strip outer bark to reach larvae; often the most visible sign in a NJ winter.
• Epicormic sprouts — frantic new shoots along the trunk and root flare as the tree tries to survive.

By the time you can see D-shaped holes and woodpecker blonding from the driveway, the infestation is usually well established — treatment decisions shouldn’t wait until spring.

Should I treat or remove my ash tree?

The decision comes down to canopy health, tree location, and value. As a rule of thumb from ISA guidance:

• Treat when the canopy is at least 70% full, the trunk is sound, and the tree has landscape or shade value worth protecting. Trunk injections of emamectin benzoate are highly effective and protect for about two years per treatment.
• Remove when dieback exceeds roughly 30–50%, when bark is sloughing off in sheets, or when the tree is near a house, driveway, or power line where failure would cause damage.

Treatment is an ongoing commitment — you are protecting the tree for the rest of its life, not curing it once. For a mature, healthy shade ash over a Livingston or Montclair patio, that math often favors treatment. For a declining ash at the back of the lot, removal usually wins.

How treatment works

Our plant health care program uses trunk-injected emamectin benzoate, applied directly into the base of the tree so the insecticide moves up into the canopy without spraying the surrounding yard. The best window in NJ is spring through early summer, once the tree is actively transporting water. Trees with more than half their canopy already gone rarely have enough living tissue left to distribute the product effectively — another reason not to wait.

Why is a dead ash tree so dangerous?

Ash is one of the most hazardous trees to remove once it dies because it becomes brittle remarkably fast. Within a year or two of death, the wood dries and the structural fibers fail, so limbs and even whole trunks can snap without warning — and dead ash are notorious for breaking apart while crews are working in them. This is why arborists price standing-dead ash removals differently and why they can rarely be safely climbed.

If you have a dead or heavily declined ash near a structure, don’t delay. A controlled tree removal now — often with a crane for the worst cases — is far safer and cheaper than an emergency call after a limb comes through the roof. For insurance claims, HOA disputes, or documentation of a hazard, we can also provide a written arborist report.

Where EAB stands in New Jersey

New Jersey is fully infested — the state and federal quarantine was lifted years ago precisely because the beetle is now everywhere, including throughout Essex and Morris Counties. If you have an untreated ash, assume it is at risk and get it evaluated. Dave Lombardi, our ISA Certified Arborist, has walked hundreds of NJ properties through the save-or-remove decision and can give you an honest read on whether treatment still makes sense for your specific tree.

Not sure if your tree is worth saving? Contact T&D Tree for a free, no-pressure estimate and an ISA-certified assessment of your ash — call (973) 434-5557 and we’ll help you make the right call before the next storm does it for you.