Field trials to quantify the long-term effect of silvicultural treatments in southern upland hardwood forests began on USDA Forest Service Experimental Forests and Ranges nearly 100 years ago. Many of those outdoor laboratories and the research sites they contain are still being examined by Forest Service scientists and their cooperators. The original field experiments began with a well-documented manipulation of stand density, structure, and composition so that scientists could monitor changes in forest characteristics for many decades. Although the original focus of the early studies was on tree growth and water quality, their research value for studying dynamics in wildlife habitat, forest health, recreation, and ecosystem function expanded exponentially with each passing decade. This report highlights early published results from many of the Experimental Forests and related sites located in the South that are pertinent to current and emerging upland hardwood forest-management issues.