Talus cone activity recorded by tree-rings of Arctic dwarf shrubs: a study case from SW Spitsbergen, Norway

Abstract

Dendrochronological methods were used to determine talus cone activity in the Arctic area. Talus cones are one of the most characteristic geomorphological features of the Svalbad Archipelago. Two species of dwarf shrubs, Salix polaris and Salix reticulata, which belong to the Willow family (Salicaceae), were collected from two talus cones located in the SW Spitsbergen Island. Th ese small creeping shrubs (less than 10 cm tall with stem diameters ranging from 0.5 cm to 1.1 cm) have well developed tree-rings which allow them to be used for dendrochronological research. Th e age of the dwarf shrubs showed the minimum time during which the cones were disturbed by mass movements. Observations and material analysis indicate that currently the talus cones are active, but their development through debris fl ow, creep and rock particle slide is observed only episodically. An increased rate of vegetation colonization during the 1980s indi