The research described in this article was conducted in the Tatra National Park in Poland, which is considered as one of the most-visited national parks in Europe. The exceptional popularity of this place is responsible for intensification of morphogenetic processes, resulting in the development of numerous forms of erosion. This article presents the outcomes of the research whose purpose was to verify the usability of unmanned aerial vehicles to check the condition of hiking trails and forests in alpine areas. An octocopter equipped with a non-metric camera was used for measurements. The paper sketches the methodology of data acquisition in harsh conditions and demanding locations of hiking trails on steep Tatra slopes. The paper also describes stages that lead to elaboration of basic photogrammetric products relying on SfM (Structure from Motion) technique. Finally, it shows the applicability of the prepared products to the evaluation of erosion along hiking trails, and to the study of plant succession or tree stand condition in the area located next to hiking trails. ...
