EN
The need for effective management of uncertainty and incomplete information is the main factor of interest in the rough set theory and multi−use methods of analysis based on this theory, both in scientific research and in solving practical problems. Rough sets can be used for processing of both non spatial and spatial data. Five areas of application of rough set in decision−support systems in forestry and forest research are presented in the study. The example of using rough sets methods for data processing in order to determine cause−effect relationships and making classification is also presented.