Patrones de infestación por insectos xilófagos en renovales de Nothofagus obliqua Mirb. y Nothofagus dombeyi (Mirb.) Oerst. (Fagales: Nothofagaceae)

Abstract

Infestation patterns of xylophagous insects were evaluated in second growth stands of Nothofagus obliqua and Nothofagus dombeyi in Valdivia, Osorno and Llanquihue provinces of Chile. The analysis addressed two scales. First, at the individual level, diameter at breast height (DBH) and canopy class (CC) of the host tree were used as predictor traits of xylophagous damage. Second, at the stand level, variables such as total tree density, host density, species richness and cover (arboreal, shrubby, herbaceous and epiphytic strata) and their asociation with infestation average were considered. The infestation mean was 9.35 % for N. obliqua and 15.89 % for N. dombeyi. At individual level both DBH and CC were positively associated with damage presence. However, the best predictor of tree infestation was DBH in both N. dombeyi and N. obliqua, greater DBH increasing the probability to find an infested tree. At the stand level, no relationship was found between insect infestation and evaluated traits in N. obliqua, whereas N. dombeyi stands with high species richness in the shrubby stratum and/or with higher total tree density and host density showed the lowest infestation levels.