Bibliogr. s. 116-119

The intensive development of ski resorts leads to significant changes in the environment. The most important issue is the increase in the susceptibility of hillslopes to erosion due to deforestation and degradation of vegetation cover. RGB-band orthophotos provided by GUGiK (Head Office of Geodesy and Cartography in Poland) were used to determine land cover changes in the ski areas of the three largest ski resorts in the Polish Carpathians for the years 2009-2019. The ski resorts were selected on the basis of their area, intensity of use and transport capacity. The ski resorts selected for the analysis were: COS Szczyrk and Szczyrk Mountain Resort in the Skrzyczne Massif, PKL Jaworzyna Krynicka in the Beskid Sądecki Mountains and Kotelnica Białczańska in the Gubałowskie Foothills. A semi-automatic image classification in ArcGIS Pro defined three land cover classes: tree cover, grass cover, and no vegetation. By comparing classes distribution, it was determined changes in the susceptibility of hillslopes to erosion. On the basis of the field surveys attention was paid to the maintain and the development of ski resorts. The results indicate that the stations located in the Skrzyczne massif developed most intensively in the 2009-2019 decade, leading to a significant decrease in tree-covered and grassy areas. Intense water erosion and mass movements on road undercuts and escarpments on ski runs were observed. The most positive changes in terms of erosion protection occurred on Jaworzyna Krynicka, where the area deprived of vegetation decreased in the studied period. This is a result of the environmental monitoring carried out and the use of various anti-erosion treatments e.g. hay spreading, sheep grazing. The research indicates that anti-erosion treatments and continuity of vegetation cover play a very important role on the possibility of erosion processes on ski run surfaces.