Dendroclimatic Studies: Tree Growth and Climate Change in Northern Forests

Historically, the growth of forests at the far northern latitudinal treeline of North America and Eurasia, as well as those at elevational treeline, has been limited largely by cold temperatures. In recent decades, with northern amplification of temperatures, largely due to anthropogenic warming, some of these forests have responded as expected with increased growth, while others have responded negatively due to drought stress. This volume describes four decades of research by a group of scientists in the field of dendrochronology, or tree–ring analysis, of northern forests and their use in large–scale reconstructions of temperature and indices of atmosphere–ocean circulation. This book takes into account the forests’ cooling response to volcanism and other climatic forcings. These records provide a long–term context for the limited instrumental record of recent decades, and a means for comparison with climate and forest growth modeling that strive to understand the causes and patterns of climatic and environmental change over the past millennium. Volume highlights include: • Long–term analysis of climatic reconstructions from tree rings. • New advanced methodologies on reconstructing past climate • State–of–the–art review of the present state of dendroclimatology and it’s future potential • Modeling tree growth environmental response • Recent warming trends which are of serious concern today • Future forecasts on global climate change Dendroclimatic Studies is a valuable contribution in Earth’s climate change studies, shedding light on recent and future climate trends by assessing long–term past climatic variations from tree–rings. Aside from geoscientists, meteorologists and paleoclimatologists, climate modelers, environmental hydrogeologists, public policy makers, and global insurance industry specialists could greatly benefit from the content of this book.

Preface  v Acknowledgments  vii 1. Introduction 1 1.1. Overview 1 1.2. Basic Tree–Ring Principles 1 1.3. Polar Amplification of Global Warming and Impacts on Forests 3 1.4. “Northern Archive” Synthesis 6 2. Tree–Ring Investigations at Northern Latitudes 7 2.1. Initial Studies 7 2.2. Site Selection 8 2.3. Tree–Ring Parameters and Processing: Ring Width and Maximum Latewood Density 9 3. Selected Local to Regional TRL–LDEO Northern Tree–Ring Studies 13 4. The Broader Context of Northern Dendroclimatic Studies 19 4.1. North America 19 4.2. Eurasia 21 4.3. Tree–Ring Chronology Networks 21 5. Temperature Reconstructions for the Northern Hemisphere 23 5.1. Initial Attempts 23 5.2. Evolution of NH Temperature Reconstructions 25 5.3. Reconstructed NH Temperature Trends 31 5.4. Standardization of NH Tree–Ring Temperature Reconstructions 33 6. Tree Growth Issues in the Anthropogenic Era: CO2 Fertilization and the “Divergence Problem” 37 6.1. CO2 Fertilization 37 6.2. The Divergence Problem 38 7. Conclusions and Future Challenges 43 Glossary 51 References 57 Core TRL–LDEO Publications on Northern Forests 67 Index 75 Color plate section is located between pages 36 and 37. 

Rosanne D’Arrigo , Lamont–Doherty Earth Observatory, Columbia University, USA Nicole Davi , William Paterson University and Lamont–Doherty Earth Observatory, Columbia University, USA Gordon Jacoby , Lamont–Doherty Earth Observatory, Columbia University, USA Rob Wilson , University of St. Andrews, UK and Lamont–Doherty Earth Observatory, Columbia University, USA Greg Wiles , The College of Wooster and Lamont–Doherty Earth Observatory, Columbia University, USA