The Hubbard Brook Ecosystem Study (HBES) sustains long-term ecological research within the Hubbard Brook Experimental Forest, a 3,160 hectare reserve in the White Mountain National Forest, New Hampshire, managed by the USDA Forest Service Northern Research Station. On-site research has produced some of the most extensive and longest continuous data bases on the hydrology, biology, geology and chemistry of a forest and its associated aquatic ecosystems.