Council looks to bolster Emerald Ash Borer treatment 

April 22 meeting indicated interest in adding funds to 2014 tree injection cycle 

The rampant destruction caused by millions of small, metallic-green Emerald Ash Borer beetles discovered in the Twin Cities has had Plymouth’s forestry efforts on high alert.

According to Deputy Director of Parks and Recreation Barb Northway, the insect has been found within 10 miles of the eastern Plymouth border.

“It will come [to Plymouth], and it will kill the trees,” Northway said.

Emerald Ash Borer is a small, exotic beetle whose larvae destroy the inner bark in ash trees, depriving the tree of necessary nutrients to survive. (File photo)

In response to the fast-encroaching range of the invasive species, the City Council held a special meeting April 22 to consider ramping up treatment measures already in place.

The exotic beetle is native to Asia and Eastern Russia and has wreaked havoc on American ash trees since it was first discovered in Michigan in 2002. The species has since spread south and across the Midwest and is a direct threat to Minnesota’s 998 million ash trees.

Moving ahead of the inevitable arrival, Plymouth outlined $17,000 in efforts to deal with the situation in the 2014 budget to inject pesticide into 338 ash trees greater than 15 inches in diameter within the city’s maintained park areas.

The work is scheduled to continue through May and June this year. Based on current research, the city would need to treat ash trees for the next 10 years to combat the destruction of the borer.

City Forester Paul Buck will spearhead the in-house treatment program. Buck proposed that the cycle be expanded to include a large number of boulevard trees as well.

Boulevard trees are considered to be within the city’s right-of-way property and Buck said he’s identified 542 ash trees greater than 15 inches in diameter in the boulevards.

Three options were offered in handling the boulevard trees:

Option A: The city will fund the injection treatment in all boulevard trees greater than 15 inches in diameter. The cost to treat the 542 ash trees would reach $35,988 every two years – a 10-year total of $179,940.

Option B: The cost of treatment would be split 50-50 between the city and the abutting property owner.

Option C: No treatment – the abutting property owners would make the decision to treat or not out of their own pockets. The city would continue to monitor the trees and would remove any dead ones at no cost to the property owner.

The beetle’s larvae leave behind these S-shaped holes, a sign of EAB infestation. (File photo)

“One of the problems with [no treatment] is that the trees would all die around the same time, and that would be a very difficult removal process,” Northway said.

City staff recommended Option A. Time is a factor, as Buck expects to begin working on park trees from east to west in the coming weeks. If council fails to act within the injection timeline, Buck said he would potentially be treating park trees while ignoring other ash trees feet away.

“The spread is continuing. It’s not stopping,” Buck said. “We’ve got a little bit of time, but not a lot.”

Included in Option A is an additional $9,529 added to the approved treatment program. Combined, it would cost the city $26,529 annually to treat the trees in the boulevard and the parks.

Buck estimated the total 10-year Option A cycle to reach about $180,000 for the boulevard trees alone. He said inaction and failure to treat would result in an estimated cost of $336,000 to remove all the dead ash trees killed by the borer.

“So after this 10-year period, we’re going to be the only city with ash trees left, essentially,” Councilmember James Prom speculated.

“These trees are likely to die anyway,” Councilmember Tim Bildsoe said. “This thing is going to get all of them eventually. It’s almost an obsolete tree to have. To me, this doesn’t make long-term sense.”

Northway noted that the borer’s food source, ash trees, would be dramatically decreased in a decade’s time, causing a dip in beetle’s numbers. She also said that a cure-all or “silver bullet” treatment could turn up within that timeframe.

“We know it’s coming,” Buck added. “If you know it’s coming, you have to make the choice.”

No action was taken, though the council did indicate enough support for the additional $9,000 in funding for 2014. The topic will be further discussed following the 2014 treatment cycle.


Contact Brian Rosemeyer at [email protected]