This master thesis is aimed at deforestation monitoring in the period from 2009 to 2017, focusing on the area of Low Tatras. Satellite radar polarimetry was used for the analysis, based on a full polarimetric ALOS data and dual polarimetric data from the Sentinel-1A satellite. Data analysis was performed in SNAP Desktop using H / A / Alpha decomposition and intensity processing. The practical part highlights the main differences of dual and full polarimetry and the possibility of change detection in the forested area of the Low Tatras. The results of the work are images showing changes in the afforestation of the area of interest over time and compared with optical images obtained from Google Earth Pro.