Long Term Trends From Ecosystem Research At The Hubbard Brook Experimental Forest

The Hubbard Brook Experimental Forest (HBEF) was established in 1955 as a site of hydrologic research in New England. The site is located within the White Mountain National Forest in central New Hampshire. The emphasis of early studies at the HBEF was the impact of forest management on water yield and quality, and flood control. The Northern Research Station of the U.S. Forest Service manages the site for longterm ecosystem research and operates an on-site field station, the Robert S. Pierce Ecosystem Laboratory.

"Since the early 1960s, the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire has been one of the most comprehensively studied landscapes on earth. This book highlights many of the important ecological findings amassed during the long-term research conducted there, and considers their regional, national, and global implications." -- P.2 of cover.

USDA Forest Service Experimental Forests and Ranges (EFRs) are scientific treasures, providing secure, protected research sites where complex and diverse ecological processes are studied over the long term. This book offers several examples of the dynamic interactions among questions of public concern or policy, EFR research, and natural resource management practices and policies. Often, trends observed – or expected -- in the early years of a research program are contradicted or confounded as the research record extends over decades. The EFRs are among the few areas in the US where such long-term research has been carried out by teams of scientists. Changes in society’s needs and values can also redirect research programs. Each chapter of this book reflects the interplay between the ecological results that emerge from a long-term research project and the social forces that influence questions asked and resources invested in ecological research. While these stories include summaries and syntheses of traditional research results, they offer a distinctly new perspective, a larger and more complete picture than that provided by a more typical 5-year study. They also provide examples of long-term research on EFRs that have provided answers for questions not even imagined at the time the study was installed.

The goal of this Third Edition is to update long-term data presented in earlier editions and to generate new syntheses and conclusions about the biogeochemistry of the Hubbard Brook Valley based on these longer-term data. There have been many changes, revelations, and exciting new insights generated from the longer data records. For example, the impact of acid rain peaked during the period of the HBES and is now declining. The longer-term data also posed challenges in that very marked changes in fluxes occurred in some components, such as hydrogen ion and sulfate deposition, calcium and nitrate export in stream water and biomass accumulation, during the almost 50 years of record. Thus, presenting “mean” or “average” conditions for many components for such a long period, when change was so prominent, do not make sense. In some cases, pentads or decades of time are compared to show these changes in a more smoothed and rational way for this long period. In some cases, a single period, often during periods of rapid change, such as acidification, is used to illustrate the main point(s). And, for some elements a unique mass balance approach, allowing the calculation of the Net Ecosystem Flux (NEF), is shown on an annual basis throughout the study.