headwater stream, bed sediment, slope-channel coupling, fluvial processes, Moravskoslezské Beskydy Mts.

Analyzed longitudinal profile of the Lubina (1.03 km) showed close relationship between between slope-channel processes, trends of aggradation or incision and mean sizes of five largest boulders. The largest sizes of boulders were observed in the uppermost parts of the profile with high intensity of sediment delivery from steep adjacted hillslopes. By contrast, much finer sediments were found in reaches of alluvial cone with recent depositional trends. General fining of bed sediments occured at 0.0-0.8 km at the transition from slope-channel coupling segment to alluvial cone, later switched to coarsening trend in recently deeply incising channel-reaches (0,8-1,03 km).