Altitudinal variation in forest composition near Lake Hankinson, Fiordland

Abstract

A description is given of forest composition and structure on a spur near Lake Hankinson, Fiordland, at approximately 500 ft intervals from the valley floor at 700 ft to near tree line at 3,000 ft. Density values are given for tree, small-tree, shrub, and herb categories and for regeneration of Nothofagus spp. which are dominant in the canopy throughout. Altitudinal gradients occur in forest composition with a rather marked change near 2,000 ft which is interpreted as a transition from lowland to upland facies of N. menziesii forest. Similar patterns are revealed in the distribution of ground and epiphytic bryophytes. From comparison with studies on Secretary Island and in the Lower Hollyford Valley, it is suggested that Fiordland forests can be regarded as a beech forest continuum, dominated largely by N. menziesii in the upland facies but, in the lowland facies, segregating into different forest types in different areas, probably under environmental pressure.