Reconstruction ability of dendrochronology in dating avalanche events in the Giant Mountains, Czech Republic

Abstract

Dendrogeomorphology represents an appropriate method for dating past avalanche events using tree-ring widths and their anatomical structure. Here, we present dendrochronological dating of avalanche events in the Giant Mountains, Czech Republic. The goals of this study were to reconstruct past avalanche activity in the Giant Mountains, and to evaluate the dating ability of dendrochronological methods by means of comparing documentary-evidenced and dendrochronologically dated avalanche events. In total, 320 cores and 12 cross-sections were extracted from 99 trees bordering four avalanche paths. We identified 1378 markers indicating possible avalanche events. Using both the number and reliability of markers, 20 very probable and 29 probable avalanche events were dated, spanning the period 1904–2012. These results significantly expand the list of directly observed avalanches compiled since the 1960s in the studied region and provided a unique possibility to validate dating results. Dendrochronological dating was relatively successful at identifying large avalanches, with 55% of such events correctly dated. However, small snow mass transports limited to the central parts of the paths were often not detected. Dendrochronological dating was also efficient at estimating spatial differences in avalanche frequency. It is concluded that dendrochronology proved to be an appropriate method to reconstruct the avalanche history of small avalanche paths of medium-altitude mountains with frequent avalanche events.