Dead Ash Trees in Maryland: Why They're Dangerous and What to Do

If you have ash trees on your property in Harford or Baltimore County, there's a good chance they're dead, dying or about to be. The emerald ash borer, an invasive beetle from Asia, has spread across Maryland and kills nearly every untreated ash it reaches.

How emerald ash borer kills ash trees

The adult beetles are small and metallic green. The damage comes from their larvae, which tunnel under the bark and cut off the tree's ability to move water and nutrients. A heavily infested tree can go from healthy-looking to dead in just a few years.

Signs your ash is infested

• Thinning and dieback starting at the top of the canopy
• Small D-shaped exit holes in the bark
• Bark splitting, with S-shaped tunnels underneath
• Heavy woodpecker activity and patches of bark stripped away ("blonding")
• Shoots sprouting from the trunk or base

Why dead ash is so dangerous

Most dead trees stay reasonably strong for a while. Dead ash doesn't. It dries out and becomes brittle quickly, so limbs snap without warning and whole trees can fail at the base. That also makes dead ash dangerous to climb and cut. Experienced crews often use equipment rather than climbers to take them down safely.

The longer a dead ash stands, the more dangerous and more expensive it becomes to remove. If it's near your house, driveway, barn, fence or a road, don't wait.

Treat or remove?

Healthy, high-value ash trees can sometimes be protected with systemic insecticide treatments, but treatment has to start before the tree is badly damaged, and it has to be repeated. Once a tree has lost a large share of its canopy, removal is usually the only safe option.

An ISA Certified Arborist consultation can tell you which trees are still candidates for treatment and which need to come down.

What we do

Goliath assesses ash trees for structure and risk, then removes them with methods that keep people and property out of harm's way. On larger properties with many dead ash, we combine hazardous tree removal with forestry mulching to clear the understory and open the land back up.