We are monitoring vegetation at the Harvard Forest for invasive plant populations with respect to land use history and other factors. Using our historical database for the Harvard Forest Prospect Hill tract, we have begun mapping the current distribution of exotic plants as a function of past land use. The 320 ha tract of Prospect Hill is mapped by parcels with known land-use history, soils, vegetation composition, and long-term vegetation dynamics. We plan to conduct annual vegetation surveys at Harvard Forest and the adjacent Quabbin Reservation to document six key exotic species currently present in the area: A. petiolata, the exotic shrubs B. thunbergii, Rhamnus cathartica, R. frangula, Lonicera spp. and the climbing vine, Celastrus orbiculatus. We will map the GPS coordinates and record cover estimates of each species and conduct spatial analyses on these data using our extensive records and GIS maps of land use histories at these locations. Detailed site histories will be determined certain species of interest, using field and archival records. Using similar techniques, we also plan to monitor invasive plant populations at key experimental plots (including the hemlock removal experiment at Simes Tract, and the "recovery phase" of the Chronic N addition plots). Together, these landscape-level studies will provide a novel historical context for understanding biological invasions in a historical context.