DYNAMICS OF FITZROYA-CUPRESSOIDES FORESTS IN SOUTHERN CHILE

Many authors have postulated regeneration failure and subsequent replacement by other species for Fitzroya cupressoides, especially in the Cordilleras de los Andes. A variety of old-growth forests in natural and man-disturbed areas was sampled to assess the regeneration of forest trees, mainly that of F. cupressoides. Gap-phase regeneration of F. cupressoides in forests of the Cordillera de la Costa and in F. cupressoides- Nothofagus betuloides and F. cupressoides-Pilgerodendron uviferum forests in the Andes is likely to maintain an uneven-aged stand structure that permits the persistence and dominance of F. cupressoides in these forests. F. cupressoides-N. nitida forest occurs on a substrate of logs, branches and coarse debris and does not represent a late-successional stage of the Fitzroya forest in the Andes. F. cupressoides, in association with Drimys winteri, Podocarpus nubigena and other species, establishes abundantly on landslides which occur frequently in the Andes. Gap-phase regeneration, occurring in different site conditions and repeated disturbance, creates a vegetation mosaic where F. cupressoides intermittently regenerates. F. cupressoides also occurs in marginal forests where the species is under the competitive pressure of well-adapted and more aggressive broad-leaved trees, which greatly inhibit its regeneration and establishment. Regeneration of F. cupressoides is abundant in exploited areas where trees were left nearby, grazing was not intense and fire was excluded. Regeneration failure of F. cupressoides for more than 25 yr in an exploited area in the Andes seems to be a consequence of the exploitation methods including large quantities of debris accumulated over extensive areas.