Biosphere Reserves and protected areas are crucial policy instruments for protecting areas of high ecological value. However, more information about land use/cover changes within Biosphere Reserves is needed, explicitly focusing on dynamics in their core, buffer, and transition zones. This study aimed to analyze the dynamics of land use/cover change between 1961 and 2018 and assess future changes from 2018 to 2034 in the Truful-Truful basin within the Araucarias Biosphere Reserve in south-central Chile. Land use/cover maps were obtained through photointerpretation of aerial photography and satellite images. Land use/cover transitions, gains, losses, and net changes were calculated for 1961-1974, 1974-1987, 1987- 2002, and 2002-2018. Future changes until 2034 were simulated using Markov chains and cellular automata. Results showed that between 1961 and 1987, 95% of the study area remained stable, with small changes associated with the succession of natural vegetation and the loss of grassland. However, between 1987 and 2018, an increase in anthropogenic activity contributed to two wildfires that affected large areas of old-growth forest in the core and buffer zones. The results indicate that wildfire events threaten the conservation of the core zone of the Biosphere Reserve due to increasing anthropogenic activities and the lack of territorial planning instruments for the buffer and transition zones of the Biosphere Reserve. Without new wildfires, natural vegetation may recover through natural or assisted ecological restoration.