Anoka County cities remove ash trees ahead of emerald ash borer invasion

Not everyone can have a maple.

That's one of the realities for homeowners who have ash trees removed and replaced as Anoka County cities deal pre-emptively with the threat of an emerald ash borer invasion.

Cities are gradually cutting down ash trees on boulevards and parks and replacing them in order to prevent the borer from quickly denuding the landscape. To avert a threat from future pests, the replacements have to be a healthy mix of oaks, lindewoods, hackberries and maples. So ... not everyone can have a maple.

Several cities are starting their seasonal ash-tree removal and replacement efforts this month. Lino Lakes crews will cut down 300 parks and wetland trees. Blaine crews will chop down 75 boulevard trees and 100 parks trees.

No infestations have been discovered in Anoka County, but scientists have found emerald ash borers in northern Ramsey County, so it's just a matter of time, Blaine and Lino Lakes officials say.

Most residents grasp the realities of preventive thinning to thwart the insect invasion. Where Blaine residents have been less understanding is when they learn they don't get to pick their replacement tree after city crews remove an ash from their ­boulevard, said Blaine Parks Department supervisor and forester Marc Shippee.

Everyone wants a maple, Shippee said.

"One of the goals is to increase the diversity of the tree population in the future. When something comes through again, it will have much less of an impact if we get away from the monoculture of trees," Shippee said.

Blaine residents who opt for a free replacement will receive one of a variety of trees including hackberries, elms, maples, lindenwoods or honey locusts. Still, about one-third of Blaine residents choose not to replace their boulevard tree, Shippee said.

Blaine has removed as many as 700 ash trees from boulevards and parks since the emerald ash borer became a threat.

With an estimated 3,000 to 5,000 ashes along boulevards and another 8,000 to 10,000 on city parkland, Blaine crews will slowly remove trees over the next decade. The city cuts down and replaces two or three ash trees along a city block or in a park area.

"Then we don't go back for five years," Shippee explained. "With Dutch Elm, neighborhoods were transformed overnight. All trees were removed and it looked like a bomb hit it. This way, we are slowly transitioning the street canopy over the next 10 to 15 years."

"Some of these are wetland trees. They are poor form, leaning and twisting and have deficiencies. We would never treat them," Asleson said.

According to a recent inventory, there are about 900 ash trees on city land and along boulevards.

Lino Lakes plans to treat certain high-value ash trees in parks and along boulevards to protect them.

In the past two years, the city has removed about 80 ash trees along boulevards and replaced them with other species including elms, oaks and hackberries, Asleson said.

The number of removals may seem high, but Asleson said Lino Lakes is in far better shape than other cities that planted large numbers of ash. "We were very careful not to over-plant ash back when people were planting ash like crazy," he said. "We planted a wide diversity of other species."

For more information, go to www.emeraldashborer.info.