Hillsboro is gearing up for a war against a small but dangerous enemy that has already invaded Vernon County and has the city in its target scope.

The enemy is the Emerald Ash Borer (EAB), a little green beetle from East Asia that was first discovered on American soil in 2002 in Michigan, and has proven to be highly destructive to ash trees and is spreading rapidly to other areas in Wisconsin, including  Vernon and surrounding counties.

The EAB is tiny, metallic green, and bullet shaped.

In the summer, the adult beetles nibble the leaves of the ash trees, but do little damage. It is the larvae that are responsible for the trees’ decline and eventual death. Within one to three years, a tree can no longer circulate the nutrients that it needs. It appears that EAB infestation is always fatal. The EAB kills all varieties of North American ash trees.

The City has developed, and the Council has approved, an official eight-year action plan to limit as much damage as possible from EAB in the coming years.

This plan will be used as a guide in dealing with EAB and dying ash trees on city property in the future.

Its total cost to the city would be $81,400.

Hillsboro’s current inventory shows 1,000 trees within the city’s streets, right-of-ways, and parks. This figure includes approximately 650 street or right-of-way trees, 260 park trees, and 90 trees in Mount Vernon Cemetery.

A total of 165 ash trees are publicly owned. Approximately 16.5% of Hillsboro’s public trees are green or white ash, 111 ash trees are on public streets and right-of-ways, and 54 Ash trees are in the parks.

With the discovery of EAB in Vernon County, there is an increased need to adequately prepare for possible infestation.

City Forester Bob Birdd, who assisted City Administrator Adam Sonntag in the formation of the EAB management Plan, said, “It’s coming but I hate to see it!

“I understand  that Westby is also dealing with a similar situation. The input from property owners is very significant in a successful outcome for Hillsboro.”

Birdd, who is largely responsible for many of Hillsboro’s “Tree City” awards, pointed out that most local folks are cooperative about problems like this and he is happy to talk with them about the plan.

Citizens should be on the lookout for any ash tree showing general signs of decline, including:

• Unusual branches produced from the tree’s base.

• Dead or dying branches in the upper crown.

• Yellow, off-color foliage in the off-season.

• D-shaped exit holes: When EAB adults emerge from beneath the bark, they create distinctive D-shaped exit holes.

• Vertical bark splits: The feeding of EAB larvae often causes a 2 to 5 inch split in a tree’s bark. In some cases larval galleries can be seen beneath these splits.

• Increased woodpecker activity. They feed on EAB larvae. Woodpecker activity that removes parches of bark may be a sign of EAB infestation.

• Presence of beetles, small enough to fit on a penny.

The city is planning an inspection program to monitor the condition of every ash tree on a regular basis. Inspections will be performed twice annually in summer and winter months.

City staff will take note of any signs of EAB decline in the tree and other tree conditions. If conditions warrant, a declining ash tree may be removed ahead of the inventory schedule.

The city will also monitor and update the tree inventory annually to reevaluate trees that need to be removed.

If a Hillsboro resident suspects that EAB has infested a tree on public property (parks or medians) or private property they should call the Department of Natural Resources EAB Hotline number (1-800-462-2803) and Hillsboro City Hall (608-489-2521).

When a street ash tree has to be removed, the city will notify the property owner with either a letter or door hanger that includes information about EAB.

The city will also develop a tree replanting program to allow residents to have a tree replanted in the place of the ash tree.