Deciduous forests in the eastern United States have been dynamic over both geological and historical time scales, particularly since humans have modified the landscape. Historically, the central hardwood forest has been subject to considerable human disturbance, especially fire, and these anthropogenic disturbances have contributed to the dominance of shade-intolerant oak (Quercus) and hickory (Carya) species within the central hardwood region. Current research indicates that many of these forests are changing to dominance by shade-tolerant species, mainly sugar maple (Acer saccharum Marsh.). This change has been attributed to a lack of disturbance. The objective of this study was to document long-term changes in structure and composition of a mature oak-hickory stand at the Ross Biological Reserve in Indiana. There has been little disturbance at the Ross Biological Reserve in the past 55 years, and a similar trend of increased shade-tolerant species was expected. Results of decadal tree censuses suggest that a successional change toward the dominance of sugar maple has been occurring during the 40-year study period, and an abundance of sugar maple saplings suggests that the increasing importance of sugar maple will continue with a lack of disturbance. The increased abundance of sugar maple may be having a negative effect on regeneration of oak-hickory species as well as on understory species such as flowering dogwood (Cornus florida L.). Such changes in the plant community also suggest changes in resources for animals. Management of the Ross Biological Reserve, and similar areas, requires an appreciation of forest dynamics on a variety of time scales.