This project will continue the research activities of the Hubbard Brook Long-term Ecological Research project (HBR-LTER), expanding upon the original theme, the effects of natural and anthropogenic disturbances on the structure and function of northern hardwood forest ecosystem. Through an integrated program of monitoring and process-level studies the investigators will examine four principal categories of disturbance: (1) silviculture and land- use, (2) air pollution, (3) changes in atmospheric CO2 and regional climate, and (4) irruptions of heterotrophic organisms. Monitoring of hydrometerology, ecosystem chemistry and biotic activity will be continued and expanded. Together with detailed, process-level studies this will allow the testing of hypotheses concerning, (1) responses of vegetation, forest floor, organic debris dams and biogeochemistry to clearcut harvesting, (2) effects of land-use changes in the Hubbard Brook Valley and the larger Pemigewasset-Merrimack Basion on ecosystem structure and function, (3) changes in loading of acidic deposition and responses of biogeochemical cycles, (4) ecosystem processing of trace metals, (5) carbon budget effects on and responses to changing atmospheric CO2 and regional climate, (6) interactions among breeding birds, phytophagous insects and vegetation structure and production, and (7) growth and longevity of fine roots and belowground herbivory. The research will be integrated using several new and existing ecosystem models.
