Complex landslide terrain in the Kamienne Mountains, Middle Sudetes, SW Poland

Dense forest hides a complex landslide terrain in the Kamienne Mountains, a part of the Sudetes range in Central Europe. Combined geomorphological, geophysical and dendrochronological research was carried out in three representative localities in order to decipher patterns of landslide evolution, to determine the extent of slope deformations, and to assess the contemporary activity of landslide terrain. Field mapping revealed the very complex nature of slope failures, both in space and time. Deep-seated sliding was the principal type of movement, and was followed by rock wall retreat by fall in the depletion zone and earthflows in the toe area. Electric resistivity survey proved useful in constraining geometry of landslide units and suggests an occurrence of underground voids in the Lesista landslide area. Dendrochronological research focused on tree-ring reduction, reaction wood, wound and scar analysis that helped to unravel the pattern of debris supply and movement subsequent to the main events, which includes free fall, talus creep, and sliding over snow cover. Today, landslide complexes are at different stages of evolution. Whereas in some places the activity has been largely completed, in others we have found the evidence for failure surfaces ready to accommodate movement. Hence, although some landslides may be relict, it is unjustified to extend this notion to all signs of hillslope instability in the area.