CONICET | Buscador de Institutos y Recursos Humanos

Wind blowdowns and avalanches are important disturbances affecting the temperate mountain forests of southern Patagonia. In previous research, we reported for the first time the occurrence of wave regeneration after wind blowdowns in continental Nothofagus pumilio forests. Furthermore, we identified the presence of avalanche channels and debris in several blowdown patches, but it is unknown how these two disturbances may interact. We undertook a retrospective study todate wind blowdown and avalanche events to study the disturbance?s interaction and to reconstruct the overall forest structure and dynamics in Nothofagus pumilio forests in Santa Cruz, Argentina. We used (i) vegetation transects along the regenerating patches and adjacent undisturbed forests to reconstruct wind blowdown events, (ii) standard avalanche reconstruction methodology to date avalanche events, and (iii) transects along the entire study area to reconstruct overall forest structure and dynamics. Mortality and establishment dates, growth patterns, and scar dates were used in each case. The frequency and magnitude of wind blowdown events was highly variable. Pre-blowdown structure of the forest and wind intensity determined disturbance severity, leading to diverse post-blowdown structures in the regeneration patches. Avalanches followed blowdown events, but older events might have taken place as well. Their impact was larger at thehighest elevation blowdown patches. The resulting stand structure exhibited a multimodal age distribution with many release events depicting the past multipledisturbance events. This study represents the first report of wind blowdown avalanche interaction for Nothofagus forests in Patagonia.