Watershed Studies at the Hubbard Brook Experimental Forest: New Lines of Investigation Stemming from a Rich Legacy of Research

The Hubbard Brook Experimental Forest was established by the USDA Forest Service in 1955 as a major center for hydrologic research in the Northeast. At that time there was heightened concern about the effects of logging on flooding and erosion, so small watersheds were instrumented for harvesting experiments designed to address this issue. The Hubbard Brook Ecosystem Study originated in 1963, with the idea of using the small watershed approach to study element flux and cycling and the response of forest ecosystems to disturbances, such as forest management practices and air pollution. The HBEF is well known as the place where acid rain was first discovered in North America and research by scientists at the site helped shape national and international acid rain policies, including the 1990 Clean Air Act Amendments. Exciting new lines of investigation at the HBEF have built on the long legacy of watershed research and there has been a shift from comparing inputs and outputs and quantifying pools and fluxes, to a more mechanistic understanding of ecosystem processes within watersheds. For example, hydropedological studies have shed light on linkages between hydrologic flow paths and soil development that provide valuable information for managing forests and stream water quality. New in situ stream chemistry sensors are collecting data at a fine temporal resolution that captures extreme events and diurnal patterns, providing new insights that were not possible with traditional weekly sampling. Plot-scale experimental manipulations, including those designed to assess effects of drought, ice storms, and soil warming and freezing are enabling us to better model and predict responses to climate change. In addition to these new research directions, there has been an emphasis on scaling up findings from the small watersheds, to the larger Hubbard Brook Valley, and Northern Forest Region to make the research more broadly relevant. Given the unprecedented environmental change that is occurring, the research at the Hubbard Brook Experimental Forest is more relevant now than ever, and will continue to serve as a basis for sound decision-making.