Phenology and germination in some rainforest canopy species at Mt Field National Park, Tasmania

Abstract

The timing of shoot expansion, flowering, germination and leaf fall was recorded in some rainforest canopy species at Mt Field National Park, Tasmania. Seed collected from these and two other species was germinated in Hobart under controlled conditions. Most of the variation in phenology and germination requirements was continuous and correlated broadly with distribution with respect to the temperature climate. The species which commonly occur at high altitudes -Athrotaxis selaginoides, A. cupressoides, Nothofagus gunnii and N. cunninghamii-germinated earlier at low temperatures than the others, with provenance variation indicated in N. cunnillghamii. The cold-sensitive species Atherosperma moschatum failed to germinate at low temperatures, with a secondary dormancy indicated. Atherosperma moschatum and Phyllocladus asplelliifolius showed delayed shoot expansion during the cool growing season of 1984-85 which rendered the shoots more frost-sensitive. The periodicity of seed production is also greatest in the high altitude species, although the ecological implications are uncertain with respect to climate. Only P. aspleniifolius shows evidence of prolonged seed dormancy. This characteristic enables the populations to survive large-scale disturbance as soil-stored seed and therefore is an important feature of the regeneration ecology of this species.