Dendrogeomorphology; High-gradient stream; Debris flow; Torrential process; Mid-mountain range; Hrubý Jeseník Mts

Culminating parts of mid-mountain ranges in Central Europe are interwoven by a network of high-gradient streams. These parts, together with the surrounding slopes, form a coupling system in which hazardous geomorphic processes, such as landslides, debris flows or flash floods, can occur. In the case of the Hrubý Jeseník Mountains (Eastern Sudetes, Czech Republic), we present an evaluation of the debris flows and related torrential processes in the high-gradient streams of the selected catchment based on dendrogeomorphic methods. In addition to the classical dendrogeomorphic approaches we refined the procedure of identifying certain and probable events using new weighted indexes for event reconstruction. Additionally, because of the steep narrow channels without a characteristic accumulation cone, a new spatial approach is defined based on the spacing of disturbed trees for each event (random distribution or clustering) and location of disturbed trees in an individual section of the valley floor.