Minnesota takes first steps against invasive ash borer

Wearing a hat to shield her eyes from the midday sun, Marilyn Grantham pointed to an ash tree that once shaded her backyard patio. Now, with most of it's branches cut off, it looks bare against the sky.

Grantham said this year the tree was the last in her complex to get foliage. She and her husband suspected something was wrong with the tree even before that.

"This was like woodpecker central," Grantham said. "We had every woodpecker within a hundred miles. We had no idea that that is what the problem was until they started cutting down trees out here along Long Avenue."

Woodpeckers are a common sign that a tree is infested with the ash borer because the birds like to eat the larvae.

Grantham says she'll miss the tree.

"You know, we're upset but we can't do anything about it," she said.

The couple bought a patio umbrella to replace the shade they've lost.

Out on the street in this St. Anthony Park neighborhood, crews shoved the last of the day's branches into a wood chipper.

Dozens of stumps poke above the ground along the street where ash trees once stood.

Rachel Coyle from St Paul's forestry unit said they'll be back until the remaining infested trees are all gone.

"The atmosphere has been pretty good," Coyle said. "People, the neighborhood - they know what is going on and they understand that some trees are going to be lost."

This is a race for the tree crews. Bug experts say it's critical to remove infested trees before the adult beetles hatch because once they do, they'll begin laying more eggs and the infestation will spread.

The adult beetles are expected to start emerging in the next few weeks.

So far, dozens of trees have been cut down. Once the rest of the infested trees are cleared, crews will return to remove the stumps.

After that, they'll begin girdling - that's where a strip of bark is cut away from a healthy tree. The tree eventually dies, but the hope is the weakened tree will attract the bugs and prevent them from spreading farther.

Crews are also hanging sticky purple traps in surrounding trees to catch the bugs.

Entomologist Mark Abrahamson said the idea is to keep the ash borers from spreading outside the infestation's core.

"The core is limited to this area," Abrahamson said. "And [it's] something that we can address to try and attack and knock back and potentially slow down the rate at which it grows and slow down the rate at which its producing satellite infestations away from it in other neighborhoods"

Experts estimate the emerald ash borer has already been in Minnesota for about four years. The symptoms are tough to spot so the beetles can live inside trees undetected for years. With more than 900 million ash trees in Minnesota, officials say it's important to stop them now.

But the beetle isn't easy to contain. It is thought to have entered the U.S. in wooden shipping crates from Asia. Soon after it was discovered in Michigan, millions of ash trees died. Until now, the bug was not known to be in Minnesota.

"So we may be without trees here for some time, at least on the boulevards," said St. Anthony resident Carol Osip.

Osip said she's hoping the city will hurry to replace lost trees.

"Everybody is sad, I mean it's shade," she said. "We love trees, that's why we live here, but I don't think there is much choice when a tree starts getting infested. I mean, this has been going on for three or four years, they say. Too bad we didn't know it sooner."

Staying one step ahead of the infestation is key, say officials.

Once they get a handle on it, they'll begin planning how to replace lost trees. Experts say planting a diversity of species will help prevent a similar episode in the future.

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