Pit-and-mound microrelief in the windthrow area in the Slovak High Tatras

Mountain slopes covered with compact stands get significantly transformed as a result of extreme processes of catastrophic type. One of the factors that cause rapid changes in the environment of such areas, including relief, are strong winds. A direct resuit of thelr action are fallen trees. They form the nucleus of development of microrelief which consists of characteristic groups of cavities and mounds. Such forms have been the subject of research within the windthrow area in the Slovak High Tatras. Within the limits of 10 polygons selected for detailed studies (total area of over 5,500 m²) all the fallen trees were measured (176 in total). It was calculated, among others, that one tree fallen during the storm in the Slovak High Tatras changed the relief of an area of approximately 3.64 m². On the average, there are 3.2 fallen trees per 100 m². Cavities and rootstocks represent 11.3% of the total area of the surveyed polygons. The estimated total surface area of the analysed forms created in just three hours on 19 Nov. 2004 is therefore about 1,400 ha (14 km²). Pit-and-mound microrelief characteristic of the studied slopes is modelled by morphogenetic processes such as falling off, wash away and deflation and get consolidated by gradually encroaching vegetation, leading to its masking. The size of the rapidly transformed land ( cavities and rootstocks, the n mounds) will increase at most by a few percent, mainly as a result of the evolution of mounds. These forms will account for 15-20% of the entire windthrow area of the Slovak High Tatras, which is typical for spruce forests transformed as a result of strong winds