A dendrogeomorphological study was run along the coast of Lake Bolsena, placed into a volcanic caldera, in the province of Viterbo, Central Italy. The study was aimed at the reconstruction of erosion present on most of the coast and was performed with samples of black poplar (Populus nigra L.) with a root system more or less uncovered. The plants showed reduction growth stress of varying intensity depending on the degree of damage to the root system from the erosion process in progress. Considering the dating of stress, the height of erosion recorded from plants and their distance from the shore line were calculated average speeds of erosion on the North, East, South and West coast. The northern and southern coast, according to the prevailing winds, are those with a greater speed of erosion of 6.4 cm/year and 9.2 cm/year respectively, 
