Parkway Trees treated for emerald ash borer

About 80 percent of the 85,000 ash trees on parkways in the city will receive a pesticide injection over the next 2 years in an effort fight off the emerald ash borer infestation.
“We think 70,000 are worth saving,” city Bureau of Forestry representative Michael Brown said of the trees. “If we don’t do something, they are all going to die. That’s the only fact that we know.”

About 19 percent of the city’s more than 500,000 parkway trees are ash trees. The city has 26 crews that are trained to inoculate the trees, and plans call for about half of the parkway trees to be inoculated this year and the other half next year.

Brown was one of several speakers who discussed efforts to save the city’s ash trees at a May 9 meeting held by Alderman John Arena (45th). About 20 people attended the meeting at the Edgebrook Clubhouse, 6100 N. Central Ave.

Without treatment, tree canopies throughout the area will be lost, said John Friedmann of the Save The Ash Tree Coalition. “If we lose these them, we lose a significant part of our fall colors,” Friedmann said.

The city has found that 99 percent of the emerald ash borer insects in a tree can be killed when inoculated with emamectin benzoate every 2 or 3 years, according to the bureau. The average cost of an inoculation is $46, compared to approximately $1,000 to remove and replace a tree.

The pesticide is injected into the tree trunk in order to kill emerald ash borer larvae that are growing under the bark. Emerald ash borer infestations begin slowly, and it can take several years before there is a noticeable decline in foliage or other signs that a tree is dying.

The city will not treat trees that are considered to be more than half dead.
The Save The Ash Tree Coalition is coordinating efforts among blocks of home owners to identify ash trees in their neighborhoods and to solicit discounts from tree companies for large orders. Friedmann said that city is only paying for treatment of trees that are on the public way.

The coalition has expressed concern that the Chicago Park District has not announced plans to treat its ash trees.

The emerald ash borer was first identified in North American in 2002, and it is believed that the insect arrived in wood packing material that was used in shipping cargo from Asia. The insect has killed more than 50 million trees in North America.

There are four types of ash trees in Chicago that the emerald ash borer is known to attack, white, green, blue and autumn purple, according to the coalition.