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Editors (peer-reviewed)

Editor , Siegwolf Rolf; , Saurer Matthias; , Roden John; , Brooks Renée
Publisher Springer International Publishing, 6330 Cham Switzerland
Volume (Issue) 8
ISBN 978-3-030-92697-7

Abstract

The annual increments of tree ring growth are a useful archive, reflecting tree environment interactions that can be precisely dated, quantified and even subdivided into seasonal time periods. This yearly datable wood material contains information about fundamental physiological mechanisms and processes (e.g. stomatal conductance, photosynthetic assimilation rates) occurring during ring formation. The analysis of the classical tree-ring width and density combined with stable C, O and H isotopes represent a reliable set of climate-sensitive proxies that reflect the impact of environmental variation on tree physiological responses. The strong link between physiology and isotope ratios is described by the well-established biophysical principles of CO2 and H2O gas-exchange and isotopic fractionation. This multiproxy approach (classical tree ring analysis combined with stable isotopes) strengthens the interpretation and provides a more reliable data set for retrospective climate reconstructions and the analysis of environmental changes. In contrast to non-living chronologies (ice cores, stalagmites etc.), trees modify base physical inputs in response to local microclimates through their physiological response to light, temperature, humidity, water availability, CO2 and nutrients. These physiological responses to moisture availability, like variation in stomatal conductance, result in subtle changes of the isotope ratios in plants. Although these changes can make interpreting isotopic variation in organic matter more complicated, it also means that these proxies can provide a wealth of additional information, if those signals can be parsed from tree-ring stable isotope chronologies. Thus, a comprehensive understanding of the combined physical, chemical and biological drivers of isotope fractionation in tree rings is crucial for retrospective interpretation. In addition, tree rings and the stable isotopes contained therein integrate dynamic environmental, phenological and developmental variation that can be used to study present organism function and recent anthropogenic influences apart from their use as proxies for conditions in the distant past. The last few decades have seen tremendous progress in isotopic analytical methods. These advances have significantly improved our understanding of the mechanisms by which tree physiology modifies stable isotope fractionation in organic matter and tree rings. This text book is the first to comprehensively cover the field of tree-ring stable isotopes. Our objective was to highlight how tree ring stable isotopes have been used to address a range of environmental issues, from paleoclimatology to forest management and anthropogenic impacts on forest growth. This compilation also provides valuable information on fundamental principles, like isotope fractionation, xylogenesis and crossdating, as well as methodological topics like sampling, analysis and standardization. The chapters evaluate weaknesses and strengths of isotope applications in tree rings. In contrast to older tree ring studies, which predominantly applied a pure statistical approach, this book focuses on physiological mechanisms that influence isotopic signals, which reflect environmental impacts. Focusing on mechanisms that link physiological responses to environmental drivers of isotope variation also clarifies why environmental impacts are not linearly reflected in isotope ratios and tree-ring widths, or why these drivers and responses are not the same on all sites. We believe this volume will be of interest to any researcher and educator who uses tree rings (and other organic matter proxies) to reconstruct paleoclimate, as well as to understand contemporary functional processes and anthropogenic influences on native ecosystems. The use of stable isotopes in biogeochemical studies has expanded greatly in recent years, making this volume a valuable resource to a growing and vibrant community of researchers.
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