Oak wilt

One reader commented on oak wilt. So here is some more information. (Don't be afraid. I'm a librarian.)

The cause of oak wilt

Oak wilt is caused by a fungus, Ceratocystis fagacearum. The fungus invades areas inside the tree where water moves. Later, balloon-like bumps called tyloses are formed and they plug up the water's path through the tree. As water movement inside the tree is slowed, the leaves wilt and drop off the tree. Red oaks are more susceptible.

If the disease is allowed to progress, it will spread to healthy oaks that are connected by the roots (root grafts) to the diseased trees. In forested areas where oak is common and root grafting is widespread, an ever-widening pocket of dead oaks will form. Where oak is mixed with other species and is a minor part of the forest, oak wilt will spread slower and may actually stop where roots are not grafted. New pockets of dead oak may also be formed by sap-feeding beetles spreading oak wilt above ground.

Dead oak trees can serve as excellent den trees for wildlife. Oaks do not decay as quickly as aspen, birch and red maple, so they will provide shelter for wildlife for many years. Also, as oaks die, the site often becomes brushy for about 10 years. Warblers, grosbeaks, cuckoos, cardinals, grouse, rabbits, deer and shrews will be attracted to the brushy area. Brown creepers may nest under the bark falling off of dead trees. Dead trees will also supply insects for birds, and large dead trees may provide perches for raptors.

As is true of nature in general, when something is dying, something else is growing or benefiting. We, however, have plenty of brush piles to shelter wildlife and leave dead but uninfected trees standing for the sake of the woodpeckers and such. So we are trying to stop the spread of the fungus on our acreage.