Caracterización florística y posición sintaxonómica de los bosques caducifolios de Nothofagus alpina (Poepp. et Endl.) Oerst. en el centro-sur de Chile
Deciduous Nothofagus alpina (Poepp. et Endl.) Oerst. trees dominate the montane forests between 200 and 1300 m a.s.l. in southern Chile (35 °- 41 °15' S). In this study the composition, structure, and syntaxonomy of Nothofagus alpina-dominated forests were investigated along their altitudinal gradient at 38 ° S in the Malleco Province, Andean Range of Chile. Additionally, a first characterization and comparison is given of the forests evaluated ecologically from microclimate and soils (which are mostly derived from late and postglacial volcanic ash deposits). Three associations are differentiated: First, the Dasyphyllo-Nothofagetum alpinae ass. nov. Frank et Finckh which occurs at lower elevations. It is differentiated as an association of the Nothofago-Eucryphion Oberd. 1960 alliance by the presence of Gevuina avellana, Hydrangea serratifolia, Lapageria rosea, and Aextoxicon punctatum. Second, the Nothofagetum procerae Oberd. ex Ramirez 1978 which occurs at middle elevations. It lacks the characteristic species of the previous alliance and is dominated by Laurelia philippiana and Nothofagus alpina. Finally, the forests on upper elevations are classified as Nothofagetum dombeyi-alpinae Esk. 1999. These forests lack evergreen broad-leaved trees and contain only Nothofagus alpina and N. dombeyi as dominant trees. The shrub and herb layer of the Nothofagetum dombeyi-alpinae is differentiated from the other associations by the presence of Maytenus magellanica, Myrceugenia chrysocarpa, Berberis trigona, and Polystichum plicatum. Generally, temperature and humidity are the main ecological factors determining the distribution of the associations. It is concluded that the Nothofagus alpina-dominated forests belong to the Wintero-Nothofagetea Oberd. 1960 em. class. This classification proposes the addition of Laurelietalia philippianae Oberd. 1960, Berberido trigonae-Nothofagetalia dombeyi ord. nov., and Wintero-Nothofagetalia ord. nov. Roig, Dollenz et Méndez orders to the Wintero-Nothofagetea class.