Permanent Plot Vegetation Sampling, 2003 Tree Data BES ID 415-

Permanent plots are a powerful tool for understanding systems over the long term because of the rigorous quantification of patterns in a spatially refined way and because of the comparability of numerous variables measured in the same place. In 1998, 7 plots were surveyed into 3 forests in the study region of the Baltimore Ecosystem Study (BES): Oregon Ridge Park (4 plots), Hillsdale Park (1 plot), and Leakin Park (2 plots). In 2003, the same seven plots were re-surveyed and one in Hillsdale Park was added, for a total of eight plots. Plots were surveyed in order to correct for slope and to achieve an accuracy of plot side length to within 0.5 cm. Plots are 1600 m2 with the exception of the Hillsdale plots which are 900 m2. The Hillsdale plots are smaller to fit within the confines of the forest patch. Sites were selected 1) to represent urban and non-urban forests, 2) away from obvious habitat boundaries or edges, 3) with consistent drainage lines within the plot, and 4) with at least 80 % continuous tree canopy. All vegetation layers were sampled in order to characterize the structure and composition of the plant community. A variety of sampling methods were used for the different layers but all layers were quantified with a high level of detail to minimize variation and to best characterize the plot.