This paper presents the effects of a landslide on vegetation located on Tymfristos mountain and more specifically in the basin of the Kati stream, Sperchios river. The landslide areas are described and related to the density and the type of vegetation. The woody vegetation developed on the gliding surface was studied using dendrogeomorphologjcal methods. In particular, the direction and tilting degree of trees as well as the deformation of trunks was compared to trees growing on a neighbouring stable surface. Subsequently, the time of mass movement reactivation was estimated using a visual growth anomaly analysis on dominant fir (Abies borisii regis Mattf.) individuals growing on the landslide. From the results it is suggested that the landslide negatively affected fir growth ring width increase at certain times without, however, nullifying it. Certain time periods are identified with intense past sliding phenomena due to increased rainfall that subsequently increased underground water.