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Article #93, March, 2005
By Bill Cook

     The words "emerald ash borer" increasingly create concern among many people in Michigan, especially forest landowners and homeowners with ash trees. Government agencies and universities have been striving to understand this exotic beetle, determine its distribution, and develop strategies to address a very serious tree pest.

     The 2002 discovery of the emerald ash borer (EAB) happened long after the beetle became well-established in southeastern Michigan and had been spread to many counties. This "artificial" spread was largely the result of humans unknowingly moving infested materials, such as nursery trees, firewood, and logs. In the world of exotic pest eradication, the EAB presents a formidable task, maybe like slamming the barn door and rounding up the horses after they ran out.

     Ideally, the introduction should have been prevented. However, millions of tons of cargo reach North American shores every year. Budgets required to inspect significant portions of imported materials are prohibitive. It is a matter of priorities, perhaps, but a fiscal reality. In the end, our collective appetite for cheaper goods will almost certainly bring more exotic pests to our shores.

     Emerald ash borers kill ash trees. There are at least 700 million ash trees in Michigan alone and all of them are at risk. Ash often serve disproportionately important roles in many settings, such as in wetlands and riparian zones. In residential areas, ash has long been a favored tree because of its fast growth, straight trunk, and until recently, minimal pest problems.

     The loss of ash is one more battle in the exotic species assault on our natural heritage. American chestnut and American elm have been reduced to a remnant of what they once were. Michigan butternut and beech are threatened by exotic pests. Balsam fir and hemlock further east are dying from exotic insects headed this way. The list continues. Many scientists believe that exotic pests are the single biggest threat to the diversity and productivity of eastern forests.

     It's important to understand that natural spread of EAB is fairly slow in most cases. Studies by MSU scientists indicate that the beetles move between 0.5 to 2 miles each year. What appears as rapid spread is actually an improved ability to find EAB.

     Finding new and low level infestations is difficult. The borers can be present in an area for several years before the trees begin to decline. Many recently discovered EAB populations have actually existed for at least a few years. Quarantine zones in southeastern Michigan expand as EAB distribution becomes better known.

     Trap-tree survey techniques were developed and tried for the first time only last year. Surveys were conducted at fairly coarse grids throughout much of Michigan because of limited budgets. They actually worked better than expected and resulted in the discovery of several "outlier" populations in northern and western Lower Peninsula. The Upper Peninsula, parts of northern Michigan, and northern Ohio and Indiana will be surveyed again this year.

     Most scientists expect additional EAB infestations to be found over the next few years. State officials have targeted the Straits area for intensive survey and detection work. If EAB populations are found in the Upper Peninsula, they will likely be a high priority for eradication.

     EAB is not merely a Michigan or Lake States issue. This exotic pest threatens at least 16 species of ash that grow across the entire continent. Efforts to reduce the density of ash in forests to help control the spread of EAB will require a considerable amount of planning and action, at a level of magnitude not often incorporated into forest management. Both public and private landowners will need to be involved. The action might be likened to setting a large backfire to stop the spread of a wildfire, except the spread of EAB is much slower than a wildfire.

     What can a landowner do? Stay current with EAB information. Visit the website: [www.emeraldashborer.info]. Response to the EAB threat needs to be carefully considered by all property owners. A single recipe for action simply does not exist. Watch for an MSU Extension bulletin about EAB for woodland owners this spring.

     If your property is not close to a known EAB infestation now, prepare for the day when new infestations are discovered on or near your property. Know which species of ash are in your woodland, where they grow, and how the ash are distributed.

     In much of the Lower Peninsula, outside of the quarantined areas, landowners should consider harvesting ash trees before quarantines are imposed. The abundance of ash, the distance from known EAB populations, and the long-term goals of the landowner are key factors in making decisions. Removing ash will help contain the spread of EAB.

     However, keep in mind that ash products such as logs, firewood, or chips cannot be moved outside quarantined areas without special permission and certificates issued by the Michigan Department of Agriculture.

     In all cases, work with a professional forester to consider the options. Be wary of unscrupulous timber buyers. Unless your land is already in a quarantine zone, you have time to learn about the EAB, work with a forester, and decide what you think is best for your property. However, don't underestimate the threat of EAB and the role that you might play in combating this serious pest.

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Bill Cook is an MSU Extension forester providing educational programming for the entire Upper Peninsula. His office is located at the MSU Upper Peninsula Tree Improvement Center near Escanaba. The Center is the headquarters for three MSU Forestry properties in the U.P., with a combined area of about 8,000 acres. He can be reached at cookwi@msu.edu or 906-786-1575.

Prepared by Bill Cook, Forester/Biologist, Michigan State University Extension, 6005 J Road, Escanaba, MI  49829
906-786-1575 (voice),  906-786-9370 (fax),  e-mail:  cookwi@msu.edu

Use / reprinting of these articles is encouraged. Please notify Bill Cook.
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