The capacity of a forest site to capture carbon and convert it into biomass defines fundamental site productivity. In the United States, the National Forest Management Act (NFMA) of 1976 mandates that this capacity must be protected on federally managed lands. Responding to NFMA, the USDA Forest Service began a soil-based monitoring program for its managed forests. Lacking an extensive research base, soil-based standards were predicated largely on professional judgment. To provide a stronger foundation, a national program of Long-Term Soil Productivity (LTSP) research was established. The LTSP program addresses both short- and long-term consequences of site and soil disturbance on fundamental forest productivity. Research centers on two key properties affecting a site's long-term productive capacity, site organic matter and soil porosity, each of which is readily influenced by management. A coordinated research network of more than 100 field installations in the United States and Canada is examining how pulse changes in these properties affect soil processes supporting vegetative growth and potential productivity. Results from installations with ≥5 years of response were presented on the 10th anniversary of LTSP, and the latest findings are assembled here. This paper describes the evolution of the study and the characteristics of the oldest field installations.
Environmental geologic studies on the United States Mid- and North Atlantic outer continental shelf area 1980-1982; Volume I, Executive summary
