No emerald ash borer signs in Coon Rapids yet

No instances of the emerald ash borer in ash trees located in the city of Coon Rapids have been reported to date.

But the city of Coon Rapids is taking a proactive approach to dealing with the problem should it occur, as it has in other parts of the Twin Cities.

Emerald ash borer (EAB) is an invasive pest introduced from Asia that kills ash trees.

The metallic wood boring beetle was first found in Detroit, Mich., and Ontario, Canada, in 2002 and has spread to other states, including Minnesota, according to City Forester Tommy Schibilla.

“The destructive potential of EAB is enormous because there is currently no known cure,” Schibilla wrote in the management plan developed by the city.

“Minnesota has 900 million ash trees vulnerable to emerald ash borer.”

Of the city’s 20,000 boulevard trees, 5,000 are estimated to be ash trees, but that does not include ash trees on private property.

According to Tim Himmer, public works director, the city has been addressing the potential ash borer problem by removing susceptible ash trees in the boulevard and replacing them with other tree species.

Chemical treatments are also an option, but staff at this time, doesn’t feel it is prudent to perform the chemical treatments because the results of such treatments are not known as of yet, Himmer told the council in response to a question from Mayor Tim Howe.

Staff will be requesting funding in the next round of budgeting to continue the current program, he said.

In 2011, the council first included money in the budget, $50,000, for EAB management.

According to Schibilla, who has been trained by the Minnesota Department of Agriculture as a Minnesota EAB first detector, boulevard ash trees in poor condition have been removed since 2010 – 51 in 2010, 99 in 2011 and 46 in 2012.

Those trees have been replaced by other tree species and no ash trees have been planted on boulevards since 1999, Schibilla wrote in a report to the council.

And as parks are reconstructed, when practical ash trees in these parks have been removed, he wrote.

Efforts have also been made to educate the public about the potential emerald ash borer problem by various means – at public events and through the media and city publications, according to Schibilla.

The average lifespan of an urban ash tree is 30 to 50 years and Coon Rapids has many in that time frame, Schibilla wrote in his report.

“The most prominent symptom of EAB is dieback of the tree canopy,” the city’s emerald ash borer management plan states.

“It is not unusual for as many as one half of a tree’s branches to die back during the first year of attack.

“The tree tries to compensate by sprouting new growth below the level of infestation.

“At this time the bark may begin to split. Eventually the adult beetles emerge from the bark and in the process, they leave a ‘D’ shaped exit hole that is about one-eighth of an inch wide.”

One reason why the city has stopped planting ash trees is because the most likely way EAB is transported is by people moving ash logs, ash firewood or infested ash trees from nurseries, according to the management plan.

For ash trees on private property, the management plan recommends that residents monitor any suspicious trees to the state departments of agriculture and natural resources or the city.

“It is recommended that residents… establish a management plan for their own property with the assistance of an ISA certified arborist,” the management plan states.

“Tree contractors removing trees in Coon Rapids need to be licensed with the city. Residents are encouraged to replace trees lost with appropriate species for the site or to plant new trees in advance of EAB.”

Peter Bodley is at peter.bodley@ecm-inc.com

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