City gears up to combat little green menace

Neighbors to the east and south are poised to decimate Wisconsin. Millions have died already in Michigan, Illinois, Indiana, Ohio, Maryland and Ontario, Canada.

Neighbors to the east and south are poised to decimate Wisconsin. Millions have died already in Michigan, Illinois, Indiana, Ohio, Maryland and Ontario, Canada.

City officials aren't waiting for the little green menace that is wreaking havoc in other states to cross Wisconsin's borders before taking action.

The city's urban forestry committee is assembling a plan to address Emerald Ash Borer in the event the destructive Asian beetle finds its way inside Wisconsin's borders.

The Wisconsin Department of Natural Resources estimates Wisconsin has about 717 million ash trees scattered throughout its forests. Ash also comprises about 20 percent of the street trees throughout the state.

The good news is only about 18 percent of the city's street trees are ash, said city forester Mary Morgan. The city, however, doesn't know how many ash trees grow in places other than city boulevards.


For those who remember the canopy of green that existed along Hammond Avenue before Dutch elm disease claimed those trees, Urban Tree Board member Dick Welch said the devastation wouldn't be nearly as bad as back then. But eradicating the problem could still be a costly venture.

Emerald Ash Borer, a shimmering green beetle about a half-inch in length, is native to eastern Russia, China, Japan and Korea. It was first identified in southeast Michigan in 2002, and has since been found in Illinois, the upper peninsula of Michigan, Indiana, Ohio, Maryland and Ontario, Canada. Small infestations in Fairfax County, Virginia, were also eradicated.

"It is 100 percent fatal to ash trees," Morgan said. "This little pest has killed at least 20 million ash trees in our neighboring state of Michigan."

It is believed the beetle found its way to the United States in ash wood used for stabilizing cargo or packing consumer products.

The beetle kills all varieties of ash, except mountain ash, which is not a true ash tree, Morgan said.

While the beetle only has a range of about one-half mile, she said, it often is transported by people moving firewood, nursery stock, logs or any part of ash with the bark attached.

"The way it kills trees is the larvae tunnel under the bark, disrupting the flow of water (and nutrients) ... and essentially strangles the tree," Morgan said.

"It would probably promulgate from the south in Illinois, where it's about 34 miles from the southern Wisconsin border," said Welch, who also serves on the Wisconsin Urban Forest Council. He said it could be two to three years before the state saw any infestations. Nevertheless, northern Wisconsin needs to be on the lookout too because the upper peninsula of Michigan is facing a second infestation, discovered near the Mackinac Bridge.


"We're really keeping our eyes open on that situation," he said.

If the pest is discovered in Superior -- or when it's discovered according to Welch, who believes it's just a matter of time -- the city would be required to establish marshaling yards to manage the disposal of the tree. Trees would have to be chipped to 1-inch square bits in order to ensure eradication, she said. While chemical treatments are being experimented with, none are 100 percent at present, she said.

The U.S. Department of Agriculture requires all ash trees within a half-mile radius of an infected tree to be destroyed as part of the eradication process.

Removing a 12-inch tree and replacing it with a 2-inch tree is estimated to cost about $740. Morgan said to replace the city's 2,148 street ash trees could come close to $1.6 million. The city is no longer planting ash, she said.

All parks and recreation employees have been trained to detect the bug, and members of the city's tree crews have received extensive training. But citizens can be part of the solution, she said.

"In Illinois, the infestation was first noticed and reported by a concerned citizen," Morgan said. "It would be wise for all of us to be on the lookout for it."

Shelley Nelson is available at or (715) 395-5022.

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