Twin Cities aim to stop spread of Emerald Ash Borer

The cities of Minneapolis and St. Paul are taking action to stop the spread of Emerald Ash Borer. Crews are removing thousands of trees a year before they rot and come down on their own.

A report from the Minneapolis Tree Advisory Commission shows the rapid spread of the insect from just a few neighborhoods near the river in 2010 to every corner of the city by 2017.

“It was just a matter of time before it was found there,” said Ralph Sievert, Director of Urban Forestry for the Minneapolis Park and Recreation Board. “Because when you find Emerald Ash Borer, it’s probably been there three or four years. It kind of takes that long before the symptoms form in the tree.”

Minneapolis is in the middle of an 8-year plan to remove all of the city’s 40,000 ash trees that were found on public property. The city is spending about $1.8 million a year from the Tree Preservation and Reforestation Levy.

“So it’s five thousand trees removed a year, and then five thousand ash replacements planted the following spring,” Sievert said.

Many of the ash trees were planted four decades ago, in the way of the Dutch Elm Disease outbreak that wiped out tree populations.

St. Paul is also in the midst of a comprehensive Emerald Ash Borer mitigation plan. Thousands of trees are also marked for removal in that city and are being treated in the meantime.

While crews can care of the problems on public property, there are perhaps many times more ash trees on private property, and those owners are responsible for treatment or removal.

“Once you know you have an ash, the choices are not real big: you can either treat the tree or remove the tree and plant a new tree,” Sievert said.

Sievert said if you plant a new tree, try to do it before you remove any ash trees, so there’s less of a gap in tree cover. Also, make sure you water any trees.  As for what type, both cities are discouraging maple trees. That’s because there are already so many, which could leave them vulnerable for the next pest or disease that threatens.