Fisionomía y sociología de los bosques de Nothofagus dombeyi en la región de Nahuel Huapi

Summary

In the mountains around Lake Nahuel Huapi three belts of vegetation can be observed: the evergreen forests of Nothofagus dombeyi between surface level of the lake (ca. 770 m a.s.l.) and 1100–1200 m; the deciduous forests of Nothofagus pumilio; and the Andean-antarctic meadows and other communities above the timberline (±1600 m).

A physiognomical study of the evergreen beech forests shows three main types of structure, one of which coincides with a quite different floristical composition.

Detailed phytosociological work following the method of Braun-Blanquet is proving the floristical relationship between the deciduous forests of Nothofagus pumilio or N. antarctica and the main part of the evergreen patagonical forests of Nothofagus dombeyi, especially when austrocedrus chilensis is present. Besides other units, there has therefore been established a new alliance, Austrocedro-Nothofagion, belonging to the Nothofagetalia pumilionis-dombeyi as an order of the Nothofagetea pumilionis-antarcticae Oberd. 1960.

Only a few stands in the extreme West of Argentine territory present the characteristics of the Nothofago-Winterion Oberd., which is an alliance of the Wintero-Nothofagetea Oberd., and corresponds to the “forêt valdivienne” of phytogeographical literature.

Comment has been made on the theoretical bases of systematics, considering that in certain cases the forest communities studied demonstrate what some ecologists think to be a “continuum” of vegetation.