City Council confronts emerald ash borer, impact on Iowa City ash trees

Although final decisions are still timid, City Council is proposing treating certain local ash trees with insecticide while cutting down several that pose public safety hazards.

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City Council confronts emerald ash borer, impact on Iowa City ash trees

An emerald ash tree is seen on Iowa Avenue on Tuesday, Sept. 4, 2018.

An emerald ash tree is seen on Iowa Avenue on Tuesday, Sept. 4, 2018.

Thomas A. Stewart

An emerald ash tree is seen on Iowa Avenue on Tuesday, Sept. 4, 2018.

Thomas A. Stewart

Thomas A. Stewart

An emerald ash tree is seen on Iowa Avenue on Tuesday, Sept. 4, 2018.

Katie Ann McCarver, News Reporter

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At a special work session Tuesday, the Iowa City City Council discussed the future of the town’s ash trees, which are suffering from an infestation of the emerald ash borer.

Many people have voiced concern about supposed plans to decimate the trees and their parasites.

“Our plan was never to destroy every ash tree,” Parks & Recreation Department Director Juli Seydell Johnson said. “We only take out trees that pose a safety hazard or must be removed for public improvement.”

Emerald ash borers are beetles native to Northeast Asia and notorious for its larvae burrowing underneath the ash trees’ bark to feed. Once trees become infected, branches thin out and become susceptible to breaking.

“It’s very difficult to identify which trees are infected,” Seydell Johnson said. “We take disease inventories, but a tree we label as healthy now might not be so a month later.”

We only take out trees that pose a safety hazard or must be removed for public improvement.”

— Parks & Recreation Department Director Juli Seydell Johnson

Contrary to popular belief, the ash tree actually represents a minority of the city’s trees, she said.

“These other trees have their own potential attackers,” Johnson said. “The majority we remove are not even ash, and for every tree we take out, we plant two in its place.”

The council agreed with the Parks & Recreation plan to chemically treat certain trees while eliminating others, strategically choosing which can be saved.

Seydell Johnson’s staff takes steps to ensure that the public is aware of what trees are being removed, especially in regards to private property. Any trees taken down in people’s front yards are the first to be replaced.

“The loss of such a mature tree canopy will be felt for decades to come,” North Side Neighborhood Association member Susan Shullaw said in an email to the council. “Ash trees provide aesthetics and shade for many residential streets, and their absence will affect property values and more.”

In her email, Shullaw suggested that the city treat as many trees as officials deem possible and better communicate with the public which trees pose safety hazards.

“Property owners, neighborhoods, or nonprofits may be interested in taking on a larger role in preserving trees,” Shullaw said. “I urge the council to adopt sensible, cost-effective principles in its response to [the ash borer].”

Many private properties have begun to respond to the ash borer, following examples set by several other cities experiencing similar infestations throughout Iowa.

“We knew this was going to happen long ago,” UI arborist Andy Dahl said. “The university’s first initial draft of the [ash borer] action plan was in 2011. But what might work for us may not work for the city.”

Because of safety concerns, Dahl and the Building & Landscape Services team will not treat the ash trees on campus  with insecticide. However, the team tries to cut down every other tree to avoid replanting a whole block.

“We were the first ones to find the pests in the county,” Dahl said. “It’s amazing how fast they swept through, the [ash borer] moves so fast. There’s a fine line between taking too many trees or not enough.”

Although Dahl predicts planting new trees will come at great expense, a more diverse tree culture may prevent further parasitic problems in the city and on campus.

“Our ash trees were planted soon after the elms were also wiped out single-handedly by Dutch elm disease, in the late-60s,” Dahl said. “If you look at this as an opportunity to diversify our campus forest, eradicating at least some of them is a good thing.”