Reading between the lines – stories of climate change and related risks as written in tree rings

WSL-Institut für Schnee- und Lawinenforschung SLF

10:30 - 11:30

Ort: Englersaal, WSL Birmensdorf (video-link to SLF Davos), max. 50 seats available

Organisatorin: Rosmarie Büchi

Referent: Prof. Dr. Markus Stoffel, Institute for Environmental Sciences, University of Geneva, Switzerland

Moderator: Georg von Arx

Sprache: English

Climate scientists often use growth-ring records of trees  to estimate temperature or precipitation conditions and thus to extend instrumental records back in time. Improved knowledge of past climate variability and extremes is fundamental for a better understanding of climate dynamics and change, but also allows putting ongoing anthropogenic warming into perspective. Trees do not only contain information on the climatic conditions of the environment in which they grow, they also keep track of past disturbances. On mountain slopes, trees are sometimes hit by rocks and boulders during rockfalls or debris flow, tilted when growing on unstable slopes or impacted by snow avalanches.

The damage left by these natural hazards can be recognized in tree-ring series in the form of scars, chaotic tissues overgrowing wounds or reaction wood. When analyzed in multiple trees growing across entire slopes, tree-ring records can not only be used to reconstruct past events and thereby complement archival records of past disasters, but also yield valuable information on process dynamics.

In this presentation, several examples will be presented from the Swiss and French Alps on how rockfall, debris flow and snow avalanche activity has evolved over the past few centuries and on how anthropogenic climate change nowadays has an influence on the frequency and magnitude of natural hazards. Based on these changes in process activity, examples will be provided on how and to what degree changes in process activity also control natural risks in mountain valleys and on how future climate change could affect process activity in decades to come.