City estimate of ash trees in Janesville parks revised from 15,000 down to 346

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Samantha Jacquest
Wednesday, August 21, 2013

JANESVILLE--An inventory showing Janesville has 346 ash trees on public property, not 15,000 as earlier estimated, has changed overnight the city's strategy for fighting the emerald ash borer, city officials said.

“We were all surprised of the small number of ash trees in our parks and public areas. I think everyone thought it was going to be in the thousands,” interim City Manager Winzenz said. “Now, this smaller number of ash trees allows the city to be more proactive.”

Parks Director Tom Presny said the earlier estimate was formed after consulting with the state Department of Natural Resources and communities of a similar size and assuming Janesville would have a similar number of ash trees.

“These were pretty broad averages, so I never took them to be accurate or refined numbers, but they were something we grabbed on to because we had no other information at the time,” Presny said.

The earlier estimates indicated 15,000 ash trees on Janesville public property, including half in developed parks. In reality, the city has only 346 ash trees in developed parks.

The city already has treated 136 of those trees against emerald ash borer, and the city's goal is to treat all 346 this year, Winzenz wrote in a memo.

The new estimate will change how the city uses its $107,000 forestry budget for 2013.

Originally, $25,000 was set aside to hire a consultant forester. Presny said the forester is not needed, now, because the city has fewer ash trees than estimated and because the emerald ash borer infestation has not gotten out of hand.

Instead, that money will go toward treating the remaining 210 trees.

Presny said it's possible the city has 7,500 ash trees in undeveloped parks, but that number is speculation and city officials have no plans to inventory those trees because they are “out of sight, out of mind.”

The estimated number of ash trees on city terraces--the area between sidewalks and curbs--also has dropped significantly. According to Winzenz's memo, earlier estimates ranged from 3,100 to 7,500 trees on terraces, but a recent drive-by survey indicates only 2,000 ash trees on city terraces.

The city will conduct a formal inventory of terrace trees by spring 2014, Winzenz said.

It's not clear how many ash trees Janesville has on private property.

Initial city estimates indicated about 15,000 ash trees on private property. Winzenz said the city will not speculate on a new estimation and has no plan to conduct an inventory of trees on private property.

The city has been getting advice from the Wisconsin Department of Natural Resources, a professor at UW-Madison, communities that have had emerald ash borer infestations and from an intern pursuing a degree in forestry.

“One of the issues we're dealing with is the treatment options seem to change on a monthly basis,” Winzenz said.

When the emerald ash borer was first discovered in Janesville in June, the Department of Natural Resources advised the city to cut down all the affected trees. As a result, about 80 ash trees were removed from public property. Now, the city is being advised to treat the trees with either an injection or a bark spray, which could save the trees when treated every couple years, Winzenz said.

The city is treating ash trees in public areas and will host forums in September for residents to share opinions about what should happen to the other ash trees in the city.

One of the main focuses of the forum will be ash trees on city terraces. The terraces are city property but are maintained by the owners of adjoining properties.

Winzenz said one option would be for the city to take over maintenance of
ash trees on terraces, but he is not sure where the money would come from
based on the city's current budget. He estimated it would cost about $270,000 for treatments that would last two or three years.

Presny said the city will bring in education and forestry professionals to give suggestions about how to move forward and help inform the public about the options.

“We very much want to share what we know as we learn it, then listen to the community on what they think our course of action should be in the future,” Presny said.

The date for the tree forum has not yet been set, but Winzenz recommended residents watch the Janesville city website, ci.janesville.wi.us, for an announcement.

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