The causal agent of sudden oak death (SOD), Phytophthora ramorum, is predicted to eventually invade forests in the southern Appalachians. Dominant overstory, Quercus rubra, and understory, Rhododendron maximum, could be eliminated by SOD. We seek to quantify the effects of simulated SOD on vegetation and seedling establishment; soil properties; and canopy structure, leaf area, and light interception. In 2005, nine experimental plots were established at the Coweeta Hydrologic Laboratory in western North Carolina in stands containing at least 15% Q. rubra and 15% R. maximum. Plots were matched by similarity vegetation and randomly assigned treatment: control, Q. rubra girdle, and both Q. rubra girdle and R. maximum removal. Canopy light interception was estimated using spherical densiometers. Girdling of Q. rubra and removal of R. maximum occurred in early 2006. Soil respiration, temperature, and moisture were measured biweekly during the growing season in 2006 and 2007. Vegetation subplots were censused in fall, spring, and summer. Litter was collected seasonally. Preliminary analysis of soil respiration for 2006 suggests a decrease in the full treatment relative to the control and girdle only treatments, due to death of R. maximum. Since girdled trees take longer to die, we expect a lag in the girdle only treatment and lower soil respiration in 2007. In 2006, soil temperature was higher in the full treatment plots because of lack of shade. Data from this study will be used to develop a predictive model of long-term forest responses and to inform management decisions.