CONICET | Buscador de Institutos y Recursos Humanos

Mixed Austrocedrus chilensis and Nothofagus dombeyi forests occur between 1600-2000 mm of precipitation as stratified even-aged stands. Successful establishment of both species in the understory of mixed forests requires of large natural at wet sites. While the processes of population dynamics and regeneration for these species have been studied in detail in this condition, little is known at the eastern drier limit of N. dombeyi distribution. This includes A. chilensis forests with an important component of N. dombeyi in some situations. The mortality process in A. chilensis forests known as Mal del Cipres generates conditions (i.e. gaps) for the recruitment of both species. The objective of this study was to examine the population dynamics of both species in these conditions. We sampled and described the structure of 6 symptomatic stands and used dendrochronological techniques to reconstruct basal area development and regeneration establishment over time. While the diameter class distributions show similar ranges of sizes for both species, basal area development over time indicates that N. dombeyi established gradually after most the A. chilensis trees did. Likewise, we observed that the recruitment of new individuals over the past 2 decades correspond primarily to N. dombeyi individuals. The result of this study shows that N. dombeyi has the ability for establishing in postfire pure A. chilensis forests resulting in mixed unevenaged forests. This could be as a result of the gaps generated by the mortality of the overstory A. chilensis trees and the lack of competing vegetation in the understory. Although there is not enough evidence at the moment to indicate a replacement of one species by the other, it is clear that after 100 years since establishment there is an important shift in the composition of these stands.