Emerald Ash Borer

What is Emerald Ash Borer?

The Emerald Ash Borer (EAB) is a small, green boring insect that attacks and kills all trees in the Ash family (Fraxinus spp). This invasive insect has been spreading across the State of Wisconsin for the last ten years and is firmly entrenched in River Falls. About 20 percent or 1900 of our public trees in River Falls are Ash.

Emerald Ash Borer
EAB Ash tree

What is city's plan to combat EAB?

EAB is having a major impact on our urban forest and will continue to do so as long as there are Ash trees present. The city anticipates EAB to spread to its peak in three to seven years. With the assistance of our contractor CNUC, the city has evaluated the condition of all the boulevard and parks ash trees in River Falls. The plan can be found here. The goals of the city are to retain canopy and to systematically remove and replace Ash. Tree health, public safety, budget and city staff workload are key drivers of decision making. Approximately half of the Ash trees in the city have been deemed treatable and will receive treatment over the next two years, starting in spring of 2023. A reevaluation will occur in 2025 to assess the effectiveness of treatments. The other half of the Ash trees will be marked and removed over the next 10 years.

What to expect if your tree is marked for removal?

If the ash in your boulevard is seriously infected and beyond treatment or saving, you will receive a tree removal doorhanger and a white dot will be sprayed on the trunk of the tree to be removed. The City or the City’s tree contractor will remove the tree soon after the arrival of the doorhanger. The stump will be ground and the area rehabbed as soon as possible. The city will then identify a space in the boulevard to replant a new tree.

What if I have Ash trees on my property besides those in the boulevard?

You can treat it in the spring, wait for the tree to get infected and die, or remove it. The cost to treat or remove the tree is the responsibility of the homeowner.

Want to replant a tree on your property?

Planting a tree filters the air and can shade your home which helps reduce your energy bill. RFMU offers a rebate of $25-$50 for each tree you plant. Simply plant a tree, take a picture, and following the application instructions.

What does this mean for residents?

There are a few options you can take to help fight the spread of EAB. If you have or think you have an Ash tree or an infected Ash tree on your boulevard and want to know your options for removal, please contact the City Forester Mike Noreen at 715-426-3467 or by email.

Visit the links below or the Urban Forestry FAQ page here for more information.

Emerald Ash Information