Its pretty devastating; Ash tree killer could be coming, says parks director

About 60 to 70 percent of trees in Powell are ash of one kind or another. Around 500 of those are city-maintained trees, according to Parks Superintendent Del Barton, who also is the city arborist.

But Les Koch, Wyoming State Forestry Division forest health program leader in Cheyenne said the ash borer may or may not arrive in Powell.

Yes, its possible, I would say distinctly low-risk at this time, Koch said.

Boulder is the only place this side of the Mississippi River that the ash borer has been discovered. And, its being contained.

As of this date, the insect has not been detected in Wyoming, Koch said.

There are thousands of privately owned ash trees in Powell, Barton said. All are at risk from the small bugs with the metallic green shell.

Emerald ash borer eggs are laid on the outer bark of trees. After the eggs hatch, the larvae burrow beneath the bark. The larvae eat phloem, the nutrient-transporting system under the bark, and that creates tunnel-like galleries.

As more galleries are eaten, the tree soon begins to exhibit symptoms of dieback (begins to die), including thinning and dying treetops, and sprouting from the base or trunk.

It costs $1 per circumference inch to treat a tree, likely with a chemical known as imidacloprid. If the trees range from 20- to 40-inch circumference, thats $20 to $40 per tree.

Estimating about 500 public ash trees, the math shows the cost at $10,000 to $20,000 per year just for the imidacloprid, Barton said.

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Its pretty devastating; Ash tree killer could be coming, says parks director