CONICET | Buscador de Institutos y Recursos Humanos

Proper management of woody ecosystems is fundamental for human livelihoods and biodiversity conservation. Strip cutting or selective harvesting are proposed as sustainable alternatives to clear-cut logging. However, their impacts are not fully understood, especially when we consider the harvesting intensityintensity levels and the invasibility of an ecosystem by nonnative tree species. In this study we analyzed the impacts of different harvesting intensity levels on the establishment after two years of nonnative and native tree species. We conducted this study in a mixed forest dominated by Nothofagus antarctica, where we applied four strip harvesting levels: 0% (control), 30%, 50% and 70% percentage of vegetation removal in eight8 plots (1. 417.5 m2 each plot) Inside those plots, we had a total of 24 subplots (3 sites x 8 plots) were we sowed planted seeds of a total of six6 tree species, that can form dominant stands in the studied region. Three species were nonnative invasive species s in the region (Pinus ponderosa, Pinus contorta and Pseudotsuga mensiezii), and the other three were native species (Austrocedrus chilensis, Nothofagus obliqua and Araucaria araucana). We found that in the high harvesting intensity treatments, the establishment after two years of all nonnative trees and only one native species (A. araucana) was increased in spite of the ecological and structural differences (i.e., productivity levels) between sites. Our results suggest that strip cutting could promote the establishment of some native trees, but harvesting intensity levels was species specific . Invasion by nonnative tree species can have important negative economic and ecological consequences on the logged ecosystems, so their removal may be required to keep them away from colonizing and dominating the logged areas, especially at high harvesting intensities.

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