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Ten years after clear-cutting forest stands in Virginia and West Virginia, competing hardwoods around American chestnut trees were either periodically cut (managed) or not cut (control or unmanaged). Blight epidemics occurred in all clear-cut plots prior to their establishment in 1984. For the control plots, the number of chestnut sprout clusters (group of stems sprouting from a single stump) with blighted live stems had decreased by 1989, but between 1985 and 1988 there was a general increase in blighted chestnut stems for the managed clearcut plots. The number of apparent superficial cankers increased in two of three managed plots between 1986 and 1989. Survival of chestnut clusters was high in managed plots between 1985 and 1989, but decreased in one control plot to zero by 1988. Mean diameters at breast height of measurable chestnut stems (> 0.8 cm) declined or remained constant in control plots, but generally increased in managed plots after initial declines. Similar but greater responses were observed in a plantation of American chestnut. Unmanaged clearcuts with a high survival of chestnut clusters had low stand basal areas for competing hardwoods, and vice versa. A mesic site favored American chestnut growth and apparent superficial cankers in the absence of competing hardwoods. Key words: chestnut blight, hypovirulence, biocontrol, forest competition.

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