LANDSLIDES IN FORESTED SLOPES IN THE MÃE LUZIA RIVER WATERSHED, TREVISO – SANTA CATARINA STATE, BRAZIL

Abstract

The state of Santa Catarina has a vast history of mass movements, especially shallow translational landslides. The Mãe Luzia River Basin, located in the municipality of Treviso, drains 22.39 km2 of the escarpment of the Southern Brazilian Plateau, and has records of landslides on slopes. The objective was to relate mass movements with past agricultural practices and the occurrence of fire in the study area. For this, the relationship between the forest and the water cycle, root system and slope stabilization was investigated, as well as soil-repellency surfaces, formed from forest fires. From aerial photographs from 1957, it was possible to correlate space-time movements of mass with anthropic practices of the past. As a result, 337 landslide scars were interpreted, mostly on the vegetation class in an advanced successional stage, which had, however, undergone selective cutting of trees and forest fire. It was concluded that the land use practices developed intensively, contributed to the suppression of large trees, which in theory, would anchor the soil and assist in its stabilization. Thus, forested areas that have suffered anthropic interference are less effective in containing mass movements, although it contributes to reducing their frequency.