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Wisconsin's ash trees don't know what's coming, but state scientists, researchers and foresters do, and they're preparing for the arrival of a dreaded tree killer.

That killer is the Emerald Ash Borer (EAB), a small, emerald green beetle that hitchhiked from Asia to the Midwest inside cargo packing materials. It was first discovered in the Detroit, Michigan area in 2002 and has since spread throughout Michigan including the Upper Peninsula, and has been found in Ohio, Indiana, West Virginia, Pennsylvania, Maryland, Illinois and Ontario. In August of 2008, the first confirmed EAB infestation was discovered near Newburg, Wisconsin in Ozaukee and Washington counties. The Emerald Ash Borer feeds on tissue beneath the bark of true ash trees (Fraxinus spp) and kills them. EAB is 100 percent fatal to ash trees of any age, size or health.

The potential devastation wrought by Emerald Ash Borer upon Wisconsin's urban and community forests could exceed that of any other forest pest in the recent past. Ash trees are common in both rural and urban areas throughout the state, but EAB will strike cities and villages especially hard. Though ash makes up about 7% of trees in the state's rural forests, it makes up about 20% of the trees in our urban forests. In some Wisconsin communities, the proportion of ash is much higher. Ash, especially green ash, is very common in urban areas because it was a popular replacement for the American elm.

EAB is not a "business as usual" tree pest. It kills quickly and thoroughly. It has completely overwhelmed the municipal staff & budget resources of most communities in infested areas.

Because dead and dying trees pose risk to life and property, urban ash management options consist of tree removal or pesticide treatment. Tree removal can be reactive once trees are infested, or preemptive to trees that are not infested. Because the financial, environmental, and social impacts of EAB can be acutely high, many communities in EAB's path have chosen to soften the blow through gradual, prioritized, preemptive removal of some of their public ash trees. A municipal tree inventory is invaluable for prioritizing preemptive removals because it can identify ash trees in poor condition, with excessive maintenance needs, in conflict with utility lines or other problem trees. Under the circumstances, removal of such trees is not difficult to justify.

 
EAB was recently discovered in Vernon County, 20 miles from La Crosse and is expected to inevitably appear in municipalities across Wisconsin. Ignoring EAB will not make it go away. In fact, the longer municipalities wait to prepare, the greater the burden on local budgets and staff. State and federal agencies cannot eliminate EAB for us. There is no government funding source to pay local costs for EAB, though limited funds may be available for specific uses such as education.

UWL has completed a tree inventory and has developed an EAB management plan. A major component of this plan will be to begin prioritized preemptive removal of ash trees that are poorly sited, of poor vigor, or are in strong competition for space with trees of a more desirable species. Over a period of several years we will continue to gradually remove ash trees from our inventory. As ash trees are removed replacement trees will be planted on campus. However, site conditions will be taken into consideration and the new tree may be planted in a more suitable location elsewhere on campus. We will also continue to use the tree inventory as a guide to choose species for planting that will create a diverse mixture of species on campus. UWL does not anticipate using pesticide treatment. This approach would require costly annual treatment of each individual ash tree for the life of the tree, causing this option to be cost prohibitive.

There is no way to know when EAB will first be found in La Crosse. The recent discovery of EAB in Vernon County reinforces the fact that EAB may already be in La Crosse and we just don't know it yet. We will continue to monitor the spread of EAB. Depending on how rapidly that spread occurs, our management plan may need to be accelerated at some point. By being proactive and beginning to prepare for its arrival, we hope to avoid both a financial and safety crisis when it does arrive. The first preemptive ash tree removals began in 2009 and continue today. For more information about the Emerald Ash Borer please visit:http://emeraldashborer.wi.gov/

For more information about UWL's EAB management plan you can contact Hank Klos at 785-8589