Oak Decline

Among physiographic subregions, the Southern Appalachian and Ozark-Ouachita Mountains are most affected. Species in the red oak group suffer greater impacts than those in the white oak group (Gysel 1957, Oak and others 1988).

Oak Decline

Although most of the decline-affected area is on privately owned land, national forests have by far the highest incidence of this problem because they have a higher frequency of stands with the attributes that favor this disease (older aged oaks predominate, oak species composition favoring susceptible species, and average to low site productivity [Oak and others 1991, 1996]). Among national forests, the George Washington and Jefferson have the highest incidence of oak decline.

The relative importance of oak is both a biological and a social question, but the cumulative impacts of the loss of American chestnut, continued oak decline, and ongoing defoliation by the gypsy moth indicate that special efforts must be made if the oaks are to maintain their prominence in the forest. Risk rating models have been developed to aid in this process (Oak and Croll 1995, Oak and others 1996, Oak and Courter 2000).

Oak decline will continue to be a forest health problem, particularly on national forest land. Oaks will not be eliminated from affected areas, but their numbers and diversity will be reduced. Red maple, blackgum, and other relatively shade tolerant species are likely to replace the oaks. As this change occurs, forest structure becomes more complex, the quantity of standing trees and woody debris increases, and overall susceptibility to oak decline and gypsy moth is reduced.

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