This project will continue the Long-term Ecological Research (LTER) at the Hubbard Brook Experimental Forest in an effort to improve general understanding of the mutual influences of environment, disturbance, biological activity and the flows of energy and materials in forest landscapes. This integrated program of long-term monitoring and process-level studies at Hubbard Brook and other regional sites address a series of hypotheses in two thematic categories: biogeochemistry and vegetation dynamics. The biogeochemical studies focus on the cycles of carbon, nitrogen, calcium, and sulfur and build especially upon a 30+ year record of fluxes from the Hubbard Brook Experimental watersheds to address several striking and surprising observations about element cycling in northeastern forests. In addition, investigations of vegetation and primary productivity at the landscape scale will be expanded, focusing upon the interactions between tree spatial distributions, soil and glacial till properties, and nitrogen cycling and nutrition. This research will be synthesized and integrated using simulation models and in the form of monographic overviews of elemental cycles.
