Titre du document / Document title

Austrocedrus chilensis and Nothofagus dombeyi stand development during secondary succession, in northwestern Patagonia, Argentina

Auteur(s) / Author(s)

DEZZOTTI A. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Forestry, Wageningen Agricultural University, 6700 AH, Wageningen, PAYS-BAS

Résumé / Abstract

Copyright (c) 1996 Elsevier Science B.V. All rights reserved. In northwestern Patagonia, Argentina, at low and mid elevations between 36°−43°S, the forests are composed of the xeric cypress Austrocedrus chilensis and the mesic southern beech Nothofagus dombeyi. The effects of the strong east−west environmental gradient, caused by the Andes rain shadow and the changing topography, on the relative composition and dynamics of these evergreen temperate forests are striking, and this is reflected in a clear vegetational zonation. A mixed A. chilensis-dominated undisturbed post-fire stand, located on a dry north-facing slope, was examined regarding size and age structures, spatial patterns, growth and regeneration. Inferences on the community dynamics were made. Density and basal area of adult trees were estimated at 776 individuals (ind.) ha⁻¹ (78.4% of A. chilensis) and 72.1 m² ha⁻¹ (67.7% of A. chilensis), respectively. Density of saplings was 360 and 2840 ind. ha⁻¹ for A. chilensis and N. dombeyi, respectively. Average radial growth rates in adults were 1.5 and 3.1 mm per ind. year⁻¹ for A. chilensis and N. dombeyi, respectively. Because of its lower density and higher growth rates, N. dombeyi constituted widely spaced, big emergent trees of the stand. In 1860 both tree species began to colonize an heterogeneous site, following a fire that eliminated the original vegetation. This period lasted 60 to 70 years, after which recruitment ceased probably in response to canopy closure, which resulted in the present even-aged clustered adult tree populations. The build-up of the A. chilensis-dominated mixed stand probably improved local moisture conditions, encouraging establishment of the N. dombeyi seedlings, and resulting in the current-day stand structure: a sapling population dominated primarily by N. dombeyi, underneath a mature overstory dominated primarily by A. chilensis. Due to the differences in abundance and growth of the regeneration between both tree species, N. dombeyi is expected to gradually become dominant or even completely replace A. chilensis. These results, together with others described in the literature, suggest that divergent development patterns occur in A. chilensis−N. dombeyi mixed stands, probably because these forests grow under a spatially varied environment and their responses vary consequently.

Revue / Journal Title

Forest ecology and management   ISSN 0378-1127   CODEN FECMDW 

Source / Source

1996, vol. 89, n^o1-3, pp. 125-137

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Amsterdam, PAYS-BAS  (1976) (Revue)

Mots-clés anglais / English Keywords

Vegetation succession ; Argentina ; Forests ; Population structure ; Perturbation ; Growth ; Natural forest regeneration ; Nothofagus dombeyi ; South America ; America ; Fagaceae ; Dicotyledones ; Angiospermae ; Spermatophyta ; Hardwood forest tree ; Coniferales ; Gymnospermae ; Softwood forest tree ;

Mots-clés français / French Keywords

Succession végétation ; Argentine ; Forêt ; Structure population ; Perturbation ; Croissance ; Régénération forestière naturelle ; Nothofagus dombeyi ; Patagonie ; Austrocedrus chilensis ; Amérique du Sud ; Amérique ; Fagaceae ; Dicotyledones ; Angiospermae ; Spermatophyta ; Arbre forestier feuillu ; Coniferales ; Gymnospermae ; Arbre forestier résineux ; Cupressaceae ;

Mots-clés espagnols / Spanish Keywords

Sucesion vegetal ; Argentina ; Bosque ; Estructura población ; Perturbación ; Crecimiento ; Regeneración forestal natural ; Nothofagus dombeyi ; America del sur ; America ; Fagaceae ; Dicotyledones ; Angiospermae ; Spermatophyta ; Arbol forestal frondoso ; Coniferales ; Gymnospermae ; Arbol forestal resinoso ;

Localisation / Location

INIST-CNRS, Cote INIST : 17223, 35400006131156.0024