Role of Acacia Spp. In Nutrient Balance and Cycling in Regenerating Eucalyptus regnans F. Muell. Forests. I. Temporal Changes in Biomass and Nutrient Content

Abstract

Following severe fire in high-rainfall Eucalyptus regnans forests, several Acacia species may germinate in large numbers. Large amounts of nitrogen, calcium, magnesium and potassium are immobilized in the Acacia biomass, much of which is returned to the soil after canopy closure. Within 3 years of a regeneration burn, 280 kg N ha-1 was in the above-ground Acacia biomass and litter layer. The relative abundance of nitrogen in Acacia spp. is a result of N fixation. The probable rate of N fixation appears significant in relation to losses of nitrogen associated with slash-burning. It is concluded that the Acacia spp. may be important in the secondary succession through nutrient conservation, replacement and redistribution.