Big jump in number of ash trees infested by EAB

There’s a sharp increase in the number of Eden Prairie trees infested with the Emerald Ash Borer (EAB), an invasive beetle known to damage ash trees and spread quickly.

The numbers are adding urgency to the City of Eden Prairie’s response: ask property owners to treat undamaged ash trees and remove the infested trees that have been marked with an orange ring of paint.

The city is still working on its annual winter survey and marking of infested ash trees in Eden Prairie, but already the number is around 900, said Matt Bourne, parks and natural resources manager for the city. That compares to about 130 infested ash trees documented a year ago, and about 20 the year before that.

The annual survey is done in winter so that city tree inspectors can see into the leafless crown of the tree, where tell-tale signs of the borer can be found.

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While many property owners are treating ash trees to protect them from EAB, 99 percent of the trees left untreated will die from the pest and need to be removed, according to the city.

The infested ash trees have been marked with orange rings in recent weeks and property owners are being notified by mail about the need to remove the trees. Property owners must pay removal costs, but the city will haul away the downed tree if left at the curb.

City code also provides for enforcement. If a property owner ignores the removal notice and deadline, the city can remove the tree on its own and assess the cost to the property owner.

“The big thing is we need to get the tree down” and disposed of by April to slow EAB’s spread, Bourne said. First detected in Eden Prairie in about 2015, EAB appears to be spreading to pockets beyond the eastern side of the community where treatment and removal efforts have been focused.

A lot is at stake. Bourne said that a survey of Eden Prairie performed a few years ago by the Minnesota Department of Natural Resources estimated the community has about 50,000 ash trees, mostly on private property.

Treating trees or removing them before they are infested is often less expensive than removing infested trees. Information about treatment options and the city’s EAB management plan are on the City of Eden Prairie website at www.edenprairie.org/EAB.