Dendrogeomorphological analysis of debris-flow activity on the Geisstriftbach cone
The Geisstriftbach is located between the villages of St. Niklaus and
Randa (Zermatt Valley) and has a surface of 7.5 ha. The debris-flow cone
is covered with comparably old European larch (Larix decidua Mill.) and
Norway spruce (Picea abies (L.) Karst.) trees and most trees on the cone
show obvious signs of past debris-flow activity. Over the past few years,
the Geisstriftbach has produced several debris flows, with individual
events temporarily blocking the main road connecting Visp with Zermatt.
During the largest of these events, several 10,000 cubic-meters of debris
have been mobilized from the periglacial departure zone, thus destroying
the recently opened “Europaweg” long-distance walking track.
In the framework of the RUFINE project,
detailed dendrogeomorphological analyses have been performed along the
current channel and on the cone in summer 2006 and more than 300 trees
sampled. First results on past debris-flow activity at Geisstriftbach
can be expected for fall 2007.
Contractors: Swiss Federal Office for the Environment (FOEN), Cantonal Department for Traffic, Construction and Environment (Canton of Valais)
Collaboration: Forest Ecology, Department of Environmental Sciences at the Swiss Federal Institute of Technology (ETH) Zurich
Project duration: August 2006 – September 2007
Contact: Markus Stoffel
Stoffel, M., Bollschweiler, M., Widmer, S., Sorg, A. (2010): Spatio-temporal variability in debris-flow activity: a tree-ring study at Geisstriftbach (Swiss Alps) extending back to AD 1736. Swiss Journal of Geosciences 103: 283–292. [PDF]
Sorg, A., Bugmann, H., Bollschweiler, M., Stoffel, M. (2010): Debris-flow activity along a torrent in the Swiss Alps: Minimum frequency of events and implications for forest dynamics. Dendrochronologia 28: 215–223. [PDF]
Sorg, A., Stoffel, M., Bugmann, H., 2007. Dendrogeomorphological reconstruction of past debris-flow activity along the channel of the Geisstriftbach (Valais, Switzerland). Geophysical Research Abstract 9: 07276. [PDF]