Heterogeneidad estructural y espacial de un bosque mixto dominado por nothofagus dombeyi después de un disturbio parcial

Abstract

The forests dominated by Nothofagus dombeyi are amongst the most abundant and productive forests in the South American temperate region. In the lowlands of Chile Nothofagus dombeyi-dominated secondary forests with their associated tree species are common. Their diameter distribution, spatial patterns and association between species have not been studied. In this work we quantify those patterns and test whether there is a spatial association between species in a structurally complex forest created after a partial disturbance. We established a 70 x 130 m plot (0.91 ha) in the Llancahue property near the city of Valdivia (39°48 S, 73°11 W and 150 masl). We quantified the structure and the diameter asymmetry through the Weibull probability function and the asymmetry index, respectively. The spatial pattern (random, clustered and regular) of the forest and of each species, and the spatial association (indifference, repulsion and attraction) of N. dombeyi with the main species were evaluated with the uniand bivariate Ripley functions. The spatial autocorrelation for the diameter at breast height d was evaluated by means of semivariograms. This paper reports that the size distribution is influenced by some species that either resisted the disturbance or were highly resilient due to their regeneration strategies, which is confirmed by the spatial pattern in aggregates, and a strong spatial autocorrelation for the species. We found that the spatial patterns are intraspecific, and do not affect the spatial association between dominant and subordinated trees species. Finally, we suggest that partial disturbances cause a rapid transformation from a simple to a complex structure along forest succession.