Disease Devalues Ash Trees

By Bill McAuliffe

Minneapolis, MN (July 22,2010)- Ash trees, once seen as a worthy successor to elms in the urban landscape, are now virtually worthless in some Twin Cities communities, thanks to the emerald ash borer. At least two suburbs- Savage and Prior Lake- have removed ash trees from their “significant” status list, meaning that developers can cut them down without having to replace them with anything.


In Savage, City Manager Barry Stock said their value is now minimal because the trees are likely to die in great numbers from the ash borer infestation. For developers wanting to make land ready for homes, office parks and shopping centers, not being required to replace those trees makes the work cheaper.
“Right now, the economy is still slumping: Developers and purchasers alike are looking for ways to cut their costs,” Stock said. “People like trees. But there’s a cost.”

But some say removing ash from the list of significant trees is shortsighted. “It’s a mistake not to replace it with anything,” said Ken Holman, community forestry coordinator for the Minnesota Department of Natural Resources. “Ash may be around for another 20 to 30 years…To just say you don’t have to replace an ash tree completely eliminates the benefits that a currently healthy live ash provides.” Minnesota is home to more than 900 million ash trees, the second-highest number in the nation.

Tree preservation ordinances have been around for more than a century in older cities such as Minneapolis and St. Paul, said Katie Himanga, president of the Minnesota Shade Tree Advisory Committee. In suburban communities, such ordinances generally go back a generation or less, following the Dutch elm disease epidemic.

They commonly require developers and even public agencies to replace some percentage of trees that are removed to make room for streets or buildings.
Weedy, troublesome or otherwise unwelcome landscape species such as cottonwood, willow and boxelder- and even elm- are usually exempt from the replacement formula, while oak, maple, linden and others are regarded as “significant” and must be compensated for.

Taking ash off the replacement list means a net loss of trees, Stock acknowledged. But any development will mean that, he added. Robert Engstrom, an award-winning developer whose projects emphasize open space and gardens, noted that development has stalled across the Twin Cities during the current recession, with about 30,000 residential lots sitting idle. He said developers need some flexibility in tree replacement requirements, but that replanting should be maintained. “As a developer I would still work around [ash] to a certain extent,” he said. “People still like their trees.” To date the ash borer hasn’t been detected beyond several neighborhoods in Minneapolis and St. Paul, and in Houston County in the state’s far southeast corner. The general thought is that anyone 15 miles or more from an infested site needn’t worry yet about their trees. Still, it’s expected the bug will begin killing trees beyond that territory sooner or later.

Even so, Eagan will retain its ash trees’ “significant” status. “It’s still a resource out there. We’re not ready to give up on it yet,” said Gregg Hove, city forester for Eagan. In Blaine, the city is already aiming to remove about 300 of the city’s approximately 10,000 ash trees on public land each year in advance of the ash borer, which city forester Marc Shippee expects to arrive sometime in the next five years. But the city itself is replacing every ash it removes, and ash remains on the list of trees that must be replaced by builders — “for the same reason we [include] boxelder,” Shippee said. “The idea is to get the tree replaced. It’s not so much what’s being removed.” Savage City Council Member Jane Victorey, who voted against removing the ash from the list of trees requiring replacement, said it was “premature.” “My concern is that if the ash borer really takes hold, and we’ve taken it off the list, how are we going to reforest?” Victorey asked.

In Prior Lake, the city is encouraging developers and homeowners to begin planting other trees near ash now, to mitigate the loss of shade when ash trees die, said city manager Frank Boyles. Removing ash from the “significant” list was done, Boyles said, so that builders would “no longer be penalized for taking ash down from our sites.”

“We are still every bit as committed to the urban forest as we ever were,” Boyles added. Himanga, of the Shade Tree Association, said the economics of development often don’t account for cost-saving functions trees perform, including reducing energy use in the summer and filtering and slowing the flow of storm water. “A community has to think of what is their goal with a tree protection ordinance- if it’s to protect tree cover, or is it something else,” Himanga said.

Related Resource:
Star Tribune- Disease Devalues Ash Trees