Aspects of Regeneration Ecology of Miro (Prumnopitys Ferruginea (D.Don) de Laubenfels)

Abstract

This thesis establishes a base level of knowledge about miro population size structures, and regeneration, drawing together new research and previous published and unpublished work, and indicates areas worthy of further research. A New Zealand-wide survey of selected representative populations of miro showed that most exhibit an L shaped population structure. Populations in the far north exhibit reverse J curves, which may be attributable to soil conditions there. The seedling stage of populations exhibits a reverse J curve, indicating that serf-thinning of miro occurs in individuals <1.7 m tall. Factors which appear to contribute to seedling mortality include drought, soil conditions, forest floor disturbance, and low light levels on the forest floor. Miro seedlings gain height at a steady rate of 3 - 4 cm yr-1, with no quiescence or growth stagnation, and no increased height growth in higher light levers, and do not form advance growth as a seedling bank which is released by a canopy gap. Higher light. levers result in increased branch growth activity. The miro embryo is not immature in the ripe seed. The hard integument appears to be a physical barrier to germination. Germination appears to be most abundant where there is plentiful forest floor moisture.