Mountainous areas in Turkey need to protective functions of mountain forests against natural hazards. Rockfalls are one of the natural disasters which ca use of serious risks to human lives and infrastructures in the mountainous areas. Rockfall causes injuring of tree barks, gives damage to sterns, uproots and breaks tree crowns. In recent years protective function of mountain forests gained particular interest and become an important subject of scientific researehes. Definition of rockfall, tree- rockfall interaction and effects of mountain forests on rockfall are subjects of this study.