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.

When we originally published Biogeochemistry of a Forested Ecosystem in 1977, the Hubbard Brook Ecosystem Study (HBES) had been in existence for 14 years, and we included data through 1974, or a biogeo chemical record of 11 years. Now our continuous, long-term biogeo chemical records cover more than 31 years, and there have been many changes. The most notable change, however, is that three of our coauthors on the original volume are now deceased. They are deeply missed in so many ways. In spite of the longer records, different trends, and new insights, we believe that the basic concepts and approaches we presented in 1977 represent the most valuable contribution of the original edition. They are still valid and useful, particularly for an introductory study of, or course in, biogeochemistry. Our goal in this revision is to preserve these fea tures, correct errors, and revise or eliminate misleading or ambiguous short-term data (11 years!), while maintaining approximately the original length and the modest cost.

Forest ecosystems represent a major type ofland use in Germanyand in Europe. They provide a number of functions, or ecosystem services, beneficial to humans, namely biomass production, regulation of the water- and energy cyde, C and N sequestration, erosion control, recreation, and they act as habitat for numerous species. The stability of forest ecosystems in Europe as influenced by the deposition of air pollutants has been a matter of debate for more than 20 years. Besides atmospheric deposition, other environmental conditions affecting forest ecosystems, such as temperature, CO content of the atmosphere 2 and precipitation, have significantly changed in the past and continue to change in the future. Quantifying and predicting the effects of these changes on ecosys tem functioning are achallenge to ecosystem research and also a requirement to establish sustainable use of forest ecosystems in the future. This book summarizes results of long-term, interdisciplinary ecosystem research conducted in two forested catchments and coordinated at the Bayreuth Institute of Terrestrial Ecosystem Research (BITÖK), University of Bayreuth, Germany. It does not aim to summarize all the research of BITÖ K in the past decade, which would go far beyond the studies in these two catch ments. Instead, we concentrate here on the long-term developments in the biogeochemistry of carbon and mineral elements and on the water cyde, at both the plot and the catchment scale.

This open access book describes the serious threat of invasive species to native ecosystems. Invasive species have caused and will continue to cause enormous ecological and economic damage with ever increasing world trade. This multi-disciplinary book, written by over 100 national experts, presents the latest research on a wide range of natural science and social science fields that explore the ecology, impacts, and practical tools for management of invasive species. It covers species of all taxonomic groups from insects and pathogens, to plants, vertebrates, and aquatic organisms that impact a diversity of habitats in forests, rangelands and grasslands of the United States. It is well-illustrated, provides summaries of the most important invasive species and issues impacting all regions of the country, and includes a comprehensive primary reference list for each topic. This scientific synthesis provides the cultural, economic, scientific and social context for addressing environmental challenges posed by invasive species and will be a valuable resource for scholars, policy makers, natural resource managers and practitioners.