What Tree Rings Can Tell About Earth‐Surface Processes: Teaching the Principles of Dendrogeomorphology

Abstract

A detailed understanding of how the earth surface is being continuously shaped and why it looks the way it does are essential prerequisites for an appraisal of geomorphic processes and related changes in space and time. Data on the occurrence of past geomorphic events remains, however, scarce and predictions on how the expected climate change may affect the frequency and volume of earth‐surface processes have to be based on limited datasets. Tree rings have on varied occasions proved to be a reliable tool for the acquisition of data on past events. In this article, examples are provided on how the recurrence of events can be assessed (how often?) or their timing determined with yearly and sometimes even monthly precision (when?). Based on the mapping of trees on the study site, it is also possible to determine the reach and lateral spread of events (how far?). Movement rates can be reconstructed (how fast?) or the magnitude of incidences assessed (how big?). In combination with meteorological, hydrological and/or seismological data, results from tree‐ring studies can be consulted to identify triggers of previous events (why?).

High resolution, quantitative reconstruction of erosion rates based on anatomical changes in exposed roots at Draix, Alpes de Haute-Provence — critical review of existing approaches and independent quality control of results

“…The study is based on (i) a dendrogeomorphic analysis of anatomical growth reactions in exposed tree roots, (ii) high resolution, quantitative reconstruction of erosion rates, and (iii) a calibration (accuracy assessment) of reconstructed rates with instrumental measurements. The purpose of dendrogeomorphology is to characterize and reconstruct geomorphic processes in space and time (Stoffel and Bollschweiler, 2009;Stoffel et al, 2010). The approach, first elucitated by Alestalo (1971) and further developed by Shroder (1980) and Braam et al (1987) takes advantage of the fact that trees growing in temperate climates form yearly increment rings that can be used to precisely date external disturbances.…”

Glacial Geomorphosites and Related Landforms: A Proposal for a Dendrogeomorphological Approach and Educational Trails

“…This method easily enables the establishment of the minimum age of moraines and recently deglaciated areas (Pelfini 1999), as well as being able to date trees buried under glacial deposits in order to retrace the path of glacier advance. Tree rings also play an educational role in helping to describe geomorphological processes (Stoffel and Bollschweiler 2009), landscape evolution (Sheppard 2002) and climate change (McCormik 2007).…”

Meta-analysis of dendrochronological dating of mass movements

“…On the other hand, the tension wood of angiosperms is usually formed on the upper part of the inclined stem, where the increased activity of the cambium usually occurs after inclination (Heinrich and Gärtner, 2008;Stoffel and Bollschweiler, 2009a). Typical features are low lignin content and the presence of gelatinous fibres (Heinrich and Gärtner, 2008).…”

“…Compression wood is formed in the area of the cambial zone of gymnosperms that is affected by compression, i.e., on the lower side (Stoffel and Bollschweiler, 2009a). The cells are usually isodiametric, typically with thickened cell walls (Schweingruber, 1996), which macroscopically results in an apparently darker colour.…”

“…Data regarding former mass-movement events are very useful for producing reliable estimates of their frequency and spatial extent (Stoffel and Bollschweiler, 2009a). If there are written records or eye-witness accounts of former reactivations in a given location, they can be very easily used as a source of information.…”