Tree-ring based reconstruction of past snow avalanches using two tree species at a slope in the Göscheneralp

Abstract

Snow avalanches pose a major threat to people living in mountainous regions across the world. Chronologies of such events date back centuries and are often focused on larger events and substantial damage to people and infrastructure. Dendrochronology offers methods to reconstruct snow avalanches at a specific site, when no records are available. In this thesis, silver birch (Betula Pendula Roth) and mountain pine (Pinus mugo Turra) were used in order to reconstruct snow avalanches at a site at the Göscheneralp, Uri. For this purpose, increment cores and discs were extracted and thin sections produced. Event dating was done by means of an eccentricity analysis as well as compression wood findings. Furthermore, the findings were compared to an existing snow avalanche chronology. As a result, snow avalanches were determined to have happened in years 1999, 2008, 2010, 2012, 2019 and 2021. In addition, snow avalanches were also spatially defined. The findings serve as a reasonable approximation, however should not be taken unambiguously