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Article #88, October, 2004  
By Bill Cook

     Oaks have long been a symbol of strength and represent many of the virtues associated with trees. Oaks have long been featured in the romance of forests as well as held in high regard among utilitarian users. The oaks of the Upper Peninsula and across Michigan now have a questionable future.

    Oak wilt is a disease similar to the fungus that killed millions of majestic American elms in the 1960s and 1970s. Elms still exist in our landscape but not nearly at the level they once held. Oaks may have a similar fate.

    Oaks in the red oak group have a habit of grafting roots among individuals. Through this network of common roots the fungus can spread 50 or more feet each year. Trees killed in one year stand as dispersal towers for fungal spore pads the following year, allowing the disease to spread overland as well. An oak with the smallest wound during the growing season is at risk. That's why foresters encourage people to avoid wounding oaks during this time.

    The disease has been running wild across parts of the southern U.P. for at least a decade. However, oaks have been dying at rapid rates for other reasons, too. Mature and overmature trees growing on infertile sands create a fragile health condition even in good years. With the addition of drought, insect defoliations, and a little bug called the two-lined chestnut borer; oak stands have been disappearing. It's not always easy to identify the specific cause of death with so many ongoing events.

    Oaks stand among the few trees this far north that produce "hard mast", or nuts. A large suite of wildlife species depend upon hard mast to one degree or another. The other common nut tree is beech. Oddly, this tree is also disappearing from our forest due to beech bark disease. This disease is a combination of a small insect, called a scale, and several species of fungus. Concentrations of beech in Luce County have become severely infested. The long term future looks a bit grim without the presence of oak and beech. The thought of a similar situation with maples is almost beyond comprehension, but the risk exists.

     The movement of firewood has been a major reason for the spread of tree diseases. Ten years ago this was much less of an issue. In the next few years, we will likely see many efforts to heighten awareness of the dangers of spreading forest damaging insects and diseases through firewood.

     Gypsy moth is another firewood hitch-hiker. The cool, wet spring weather in 2004 saved parts of our forest from the heavy defoliation predicted by forest health specialists. The Entomophaga fungus tore through the caterpillar populations, killing many of the larvae before they chewed through much of our forest. Nevertheless, this fall's egg mass counts are high. Once again, the stage is set for major gypsy moth defoliation in 2005.

     The latest bug that can be carried with firewood is the emerald ash borer, a pretty little green beetle responsible for killing millions of ash in southern Michigan and adjacent areas in Ontario, Ohio, and Indiana. The prognosis on whether authorities can contain the spread of this borer is not good.

     The expansive forests of the Upper Peninsula and the northern Lake States are no longer as remote as they once were. Threats from invasive species increase all the time and people are moving around more than ever. Our forests are dotted with second homes. The best hedge against this assault is education. The more we know about forests and threats to the forests, the better our behavior and decisions will become. The forest legacy we leave to the next generation will, in part, depend upon our willingness to learn and exercise caution.

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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.
By-line should read "Bill Cook, MSU Extension" Please use the article trailer whenever possible.

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