The understanding of geomorphic processes and knowledge of past events are important tasks for the assessment of natural hazards. Tree rings have on varied occasions proved to be a reliable tool for the acquisition of data on past events. In this review paper, we provide an overview on the use of tree rings in natural hazards research, starting with a description of the different types of disturbances by geomorphic processes and the resulting growth reactions. Thereafter, a summary is presented on the different methods commonly used for the analysis and interpretation of reactions in affected trees. We illustrate selected results from dendrogeomorphological investigations of geomorphic processes with an emphasis on fluvial (e.g., flooding, debris flows) and mass-movement processes (e.g., landslides, snow avalanche), where lots of data have been generated over the past few decades. We also present results from rockfall and permafrost studies, where data are much scarcer, albeit data from tree-ring studies have proved to be of great value in these fields as well. Most studies using tree rings have focused on alpine environments in Europe and North America, whereas other parts of the world have been widely neglected by dendrogeomorphologists so far. We therefore challenge researchers to focus on other regions with distinct climates as well, to look on less frequently studied processes as well and to broaden and improve approaches and methods commonly used in tree-ring research so as to allow a better understanding of geomorphic processes, natural hazards and risk.

Dendrogeomorphology Beginnings and Futures: A Personal Reminiscence My early forays into dendrogeomorphology occurred long before I even knew what that word meant. I was working as a young geoscientist in the 1960s and early 1970s on a problem with slope movements and deformed vegetation. At the same time, unknown to me, Jouko Alestalo in Finland was doing something similar. Both of us had seen that trees which produced annual growth rings were reacting to g- morphic processes resulting in changes in their internal and external growth p- terns. Dendroclimatology was an already well established field, but the reactions of trees to other environmental processes were far less well understood in the 1960s. It was Alestalo (1971) who first used the term, dendrogeomorphology. In the early 1970s, I could see that active slope-movement processes were affecting the growth of trees in diverse ways at certain localities. I wanted to learn more about those processes and try to extract a long-term chronology of movement from the highly diverse ring patterns.

Over the last few years, rockfall research has increasingly focused on hazard assessment and risk analysis. Input data on past rockfall activity were gathered from historical archives and lichenometric studies or were obtained through frequency- olume statistics. However, historical records are generally scarce, and lichenometry may only yield data with relatively low resolutions. On forested slopes, in contrast, tree-ring analyses may help, generally providing annual data on past rockfall activity over long periods. It is the purpose of the present literature review to survey the current state of investigations dealing with tree-ring sequences and rockfall activity, with emphasis on the extent to which dendrogeomorphology may contribute to rockfall research. Firstly, a brief introduction describes how dendrogeomorphological methods can contribute to natural hazard research. Secondly, an account is provided of the output of dendrogeomorphological studies investigating frequencies, volumes or spatial distributions of past rockfall activity. The current and potential strengths of dendrogeomorphology are then presented before, finally, the weaknesses of tree rings as natural archives of past rockfall activity are discussed and promising directions for further studies outlined.

This comprehensive text addresses all of the subjects that a reader who is new to the field will need to know and will be a welcome reference for practitioners at all levels. It includes a history of the discipline, biological and ecological background, principles of the field, basic scientific information on the structure and growth of trees, the complete range of dendrochronology methods, and a full description of each of the relevant subdisciplines.

Tree-ring dating (dendrochronology) is a method of scientific dating based on the analysis of tree-ring growth patterns. As author James Speer notes, trees are remarkable bioindicators. Although there are other scientific means of dating climatic and environmental events, dendrochronology provides the most reliable of all paleorecords. Dendrochronology can be applied to very old trees to provide long-term records of past temperature, rainfall, fire, insect outbreaks, landslides, hurricanes, and ice storms--to name only a few events. This comprehensive text addresses all of the subjects that a reader who is new to the field will need to know and will be a welcome reference for practitioners at all levels. It includes a history of the discipline, biological and ecological background, principles of the field, basic scientific information on the structure and growth of trees, the complete range of dendrochronology methods, and a full description of each of the relevant subdisciplines. Individual chapters address the composition of wood, methods of field and laboratory study, dendroarchaeology, dendroclimatology, dendroecology, dendrogeomorphology, and dendrochemistry. The book also provides thorough introductions to common computer programs and methods of statistical analysis. In the final chapter, the author describes "frontiers in dendrochronology," with an eye toward future directions in the field. He concludes with several useful appendixes, including a listing of tree and shrub species that have been used successfully by dendrochronologists. Throughout, photographs and illustrations visually represent the state of knowledge in the field.

This book provides a detailed overview on methods used for the dating of past torrential activity on fans and cones and fosters the discussion on the impact of past and potential future climate change on torrential processes. The book has a clear focus on the practical applications of these methods, complemented by case studies. The limits of each dating method in case of excessive natural and human interventions on fans and cones are shown.

Tree Rings and Climate deals with the principles of dendrochronology, with emphasis on tree-ring studies involving climate-related problems. This book looks at the spatial and temporal variations in tree-ring growth and how they can be used to reconstruct past climate. Factors and conditions that appear most relevant to tree-ring research are highlighted. Comprised of nine chapters, this book opens with an overview of the basic biological facts and principles of tree growth, as well as the most important terms, principles, and concepts of dendrochronology. The discussion then shifts to the basic biology governing the response of ring width to variation in climate; systematic variations in the width and cell structure of annual tree rings; and the significance of tree growth and structure to dendroclimatology. The movement of materials and internal water relations of trees are also considered, along with photosynthesis, respiration, and the climatic and environmental system. Models of the growth-climate relationships as well as the basic statistics and methods of analysis of these relationships are described. The final chapter includes a general discussion of dendroclimatographic data and presents examples of statistical models that are useful for reconstructing spatial variations in climate. This monograph will be of interest to climatologists, college students, and practitioners in fields such as botany, archaeology, hydrology, oceanography, biology, physiology, forestry, and geophysics.