Beech (Nothofagus) Forests in the Andes of Southwestern Argentina

Abstract

The subantarctic forest of Argentina extends along the Andes from about 350 S to Tierra del Fuego. The present phytosocio- logical study was concerned with the forest vegetation from 400 S to 430 S. In this region three of the six species of beech (Nothofagus) in Argentina are present. Nothofagus dombeyi, an evergreen Angiosperm, is the dominant tree over much of the mesic and wet-mesic lowland and low- er slope areas. Nothofagus pumilio, a deciduous tree, dominates the upper slope and timberline forests, while N. antarctica (also deciduous) occurs at timberline and also in the lowland areas. In areas of very heavy precipitation ( 150-200 inches/year) a rain forest dominated by Fitz- roya cupressoides, N. dombeyi, and several other tree species develops. A bamboo (Chusquea) forms moderately dense to very dense under- story growth in much of the forested area. A pronounced rain-shadow effect exists in this region so that 50 miles east of the rain forest the precipitation may be only one-tenth as much. Here Libocedrus chilensis, which occurs also in much moister areas, is the dominant tree in the forest-steppe transition.