Why is the Bark Falling Off My Ash Tree?

Many area residents are noticing a strange phenomenon – the bark on ash trees is falling off in pieces, giving the trunk a blond appearance. Often, there are small pieces of bark on the ground at the base of the tree. And sometimes you’ll see woodpeckers feverishly pecking at the tree trunk.

What’s going on?

What you’re seeing is one of the more visible signs of Emerald Ash Borer (EAB) infestation. Called “ash blonding”, it refers to the lighter color of the inner bark that becomes visible as the outer bark is removed by woodpeckers searching for borers under the bark.

What’s an Emerald Ash Borer?

EAB is the most devastating threat to Connecticut forests since Dutch elm disease and chestnut blight and far outpaces ash yellows as the leading cause of death for our ash trees. Ash trees across the state are dying at an alarming rate, with little sign of the infestation slowing down.

The emerald green insect itself is tiny – less than 0.5” long – but the borer (immature phase of the EAB lifecycle) does a lot of damage by feeding on the vessels that transport nutrients up and down the tree, cutting off the tree’s nutrient supply.

Emerald Ash Borer was confirmed in the Danbury area in 2016, with surrounding towns quickly following. The map below shows the prevalence of EAB across Connecticut in July of 2018.

How Can I Tell If My Ash Tree Has EAB?

There are several telltale signs of EAB infestation –

• The tree canopy has few leaves and/or large dead areas
• If you peel back the bark, you’ll see serpentine tunnels caused by borers feeding on the tissue
• There are tiny D-shaped holes in the bark caused by the adult borers leaving the tree

As the infestation worsens, you may notice woodpeckers aggressively tearing at the bark. They’re trying to find the beetles (to turn them into a meal) and, in the process, are also removing pieces of the tree’s outer bark. As the lighter-colored inner bark starts to show through, the tree takes on a flecked appearance. Eventually, as more and more outer bark is removed, the tree trunk starts to look blond, rather than brown.

What Should I Do?

First, determine whether or not you have any ash trees on your property. If you’re unsure, give us a call at 203-240-1302 – we’ll be happy to identify and inspect the trees on your property.

If you have ash trees, examine them closely for signs of EAB infestation. This should be done by a Certified Arborist because early signs often appear high in the tree canopy and are easy to miss.

Depending on the condition of the tree, you have several options –

If the tree is healthy:

1. Preemptively cut down the tree to eliminate the chance of EAB infestation.
2. If you’d like to save the tree, have a professional treat it with a systemic insecticide. There are no over-the-counter treatments available to homeowners in Connecticut so the insecticide must be applied by a licensed arborist.

Doing nothing is NOT an option. It’s not a case of if the tree will be infected, but when.

If the tree is infested with EAB but has no more than 30% canopy dieback:

1. Have a licensed arborist apply a systemic insecticide to protect the tree from further damage. If the infestation is caught early enough, the tree can be treated and saved.
2. Remove the tree to avoid spreading EAB to neighboring trees or properties.

If the tree is heavily infested or dead:

1. Tree removal is the only option at this point.

Hint: Signs of ash blonding usually indicate that the tree is heavily infested and/or nearly dead.

Removing a tree that has died due to EAB infestation is a tricky job that can be extremely dangerous. Ash trees lose their structural integrity when they die, leaving them prone to unexpected and catastrophic failure.

This is NOT a DIY job! Only hire a Certified Arborist with the experience, skills and specialized equipment needed to safely remove a dead ash tree. And check their insurance papers to ensure that you and the tree crew are fully protected.

If you see signs of ash blonding on your trees, would like to preserve a healthy ash tree or need to have a dead ash tree removed, please call us at 203-240-1302.

You can also learn more about our Emerald Ash Borer Treatment Program.