Laurophyllisation of deciduous Nothofagus-forests in Southern Chile

Stratified measurements of frequency of the major tree and liana species have been used to interpret the vegetation dynamics of deciduous Nothofagus obliqua forests in the Central Valley of south-central Chile. In terms of both cover and frequency, secondary forests are dominated by Nothofagus obliqua in association with evergreen and laurophyllous-indifferent species. Laurophyllous trees of Valdivian origin, such as Aextoxicon punctatum, dominate all strata of the few remaining old growth forests, most of them showing regeneration patterns typical of shade tolerant late-sucessional species. Evergreen tree species from Central Chile which reach their southern limit in the study area are most frequent in early successional stages on "zonal" sites, although their original niches in this region were "extrazonal" thermophilous sites. The current dominance of the deciduous Nothofagus obliqua appears to be a consequence of anthropogenic destruction of stands during the last century. Long periods without disturbance would cause these forests revert to evergreen broad-leaved rain forests. This laurophyllisation process appears to be controlled by land-use practice and intensity rather than by global warming. Consequently, studies on laurophyllisation should pay particular attention to landuse history and changing patterns of land-use.