We analyzed in a Chilean Andean southern basin, the intensive degradation of the forest ecosystems in the upper basin of the Palena river (43° 30' -44°00'S) Extensive fire forest produced dunng 1930 to 1955 in the Andean mountain, generated the impact of the native forest wich is predominantly Nothofagus.
The erosion and the intense geomorphic dynamic of the mountain (landslide, landslipping) have also contributed to the destruction of the tres. The controlled fire forest in order to obtain room for prairies along with the wood log extraction, are the constant anthropogenic factor in the development of this process. In the days it isrecognized, in just few places, a slow and difficult regeneration of wood species,