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Invasive Beetle Threatens Stroebe's Ash Trees

The Emerald Ash Borer is a small, shimmery green beetle native to northeastern Asia that devastates ash trees, eating the living tissues that carry its sap and nutrients. Since its arrival in the U.S. in 2002, the invasive wood-boring beetle has wreaked havoc on all species of ash trees throughout the county, from bottomland forests to urban neighborhoods.  Unfortunately, since its detection in Wisconsin in 2008, the beetle has spread throughout the state—and is expected to continue increasing the ash mortality rate in Wisconsin. 


About twenty-two percent of the state’s ash trees occur in northeast Wisconsin (Source: Wisconsin’s ash resource, WDNR). Because ash is a fairly common species throughout the region, the Land Trust is actively monitoring its own protected lands for signs of Emerald Ash Borer, and working with the WDNR to manage properties where it is already known to exist. Regrettably, the Stroebe Island Marsh Preserve (Village of Fox Crossing), forested with a large stand of ash trees, has been heavily infested. 

As the ash trees die back from beetle infestation, the leaf canopy thins, causing changes to the forest floor cover. Depending on water levels and weather conditions, NEWLT will be required to log and remove the infected trees at its Stroebe Preserve sometime within the next three years. This action is taken reluctantly, to maintain the health of the entire preserve, and to slow the beetle’s spread throughout the area. 

The upcoming ash harvest will change the look of the forest at the Stroebe marsh, but will also provide an opportunity to re-plant the area with native species. Since it’s likely that other invasive species will be the first to try to colonize any non-planted areas, NEWLT will try hard to keep them out by planting hardy, native species instead.  Ongoing efforts to control invasive plants like buckthorn, honeysuckle, garlic mustard, and reed canary grass will be ramped up in preparation for this re-planting.

Your support, and support from employees of Amcor, Cellcom, Great Northern Corporation, Kimberly-Clark, Water-Right, and others will help with the project. New plantings will be made where ash trees have been removed, or where an opening in the canopy creates a spot for regrowth. 

If you’re a homeowner or landowner concerned about the Emerald Ash Borer, resources are available to help identify, treat, and remove the insect, as well as to suggest replanting.  Please visit the links below to learn how you can spot the beetle, and how it can be managed.


Good luck!


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