JOHNSTON, Iowa (AP) — Johnston officials have decided to remove up to five dozen ash trees before an insect pest arrives to kill them.
Officials hope that planting a variety of other species will create a healthier canopy before emerald ash borers reach the Des Moines suburb. Only trees showing signs of distress will be removed.
Emma Hanigan, an urban forester for the State Department of Natural Resources, said Johnston is among the first communities in Iowa to cut down large numbers of vulnerable trees before the beetles arrive. Iowa State University has a similar program, and the City of Cedar Rapids has done removals.
The emerald ash borer can kill an ash tree within three to five years of infestation. Once an infestation hits a community, massive numbers of trees and their dead limbs could pose a safety hazard to people and property.
As a result, other cities in the Des Moines metro area such as West Des Moines and Urbandale are now considering similar removal programs. A removal program can also help spread out the costs of dealing with an infestation.
The ash borer has been detected in three counties in northeast and southeast Iowa. There are an estimated 3.1 million ash trees in Iowa cities.
The beetles are native to Asia and were first detected in Michigan in 2002. Since then the insects have stripped entire neighborhoods of ash trees, killing more than 50 million of the them.
Johnston's program is aimed at preventing that kind of damage. The city has marked about 60 ash trees that show signs of distress, including the loss of leaves and falling branches.
“I knew that just being ready for EAB (emerald ash borer) to get here wasn't really enough, that we needed to be a little bit more proactive,” said Parks Director John Schmitz.
The program also aims to diversify the tree population.
“The thought process that happened 30, 40, 50 years ago versus what is known now is totally different,” Schmitz said. “Streets lined with ash, streets lined with elm was the thing because that's what looked uniform and looked beautiful. But we now know that it's detrimental to the health of the community because you have a monoculture.”
Though it could take some time, the U.S. Forestry Service said the insect could spread to central Iowa and Polk County as early as the next four to six years. Johnston officials said there's little doubt the beetle will eventually be found in the Des Moines metro area.
“It's not a question of if, it's a question of when,” said Tracy Irwin, Johnston's city arborist.
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