Much of the current uncertainty regarding the nature and mechanisms of forest succession is a consequence of the paucity of long-term data sets, particularly those dealing with the patterns of establishment, growth, and mortality of individual plants. Measurements of long-term data sets in the Duke Forest, North Carolina will be continued under the aegis of the Long-Term Research in Environmental Biology (LTREB) program. These data sets include: 1. Permanent Sample Plots (PSPs). These plots were established between 1931 and 1947 in stands representing an array of site conditions and successional stages. Individual trees in these 51 permanent plots have since been censused and measured at roughly 5-year intervals. These data will be used to examine long-term changes in tree growth and mortality, 2. Intensive Seedling and Sapling Plots. In these plots, established in stands representing an array of site and successional conditions in 1977, mapped individual seedlings have been censused annually. Monitoring of intensive plots in thinning- and transition-stage pines, and hardwood stands will continue. The sampling protocol will include sapling populations. These data will facilitate studies of mechanisms of transition from even-aged pine to uneven-aged hardwood forests, as well as long-term trends in seedling and sapling demography, 3. Mapped Forest Plots. Permanent mapped forest plots representing transition pine- hardwood stands and hardwood stands will be resampled. These data will be used to address a variety of a questions related to successional changes in pattern and stand structure.
