Composition, leaf area index and standing biomass of eucalypt open forestsnear Darwin in the Northern Territory, Australia

Savanna communities dominate the wet dry tropical regions of the world and are an important community type in monsoonal northern Australia. As such th ey have a significant impact on the water and carbon balance of this region . Above the 1200-mm isohyet, savanna's are dominated by Eucalyptus miniata E. tetrodonta open forests. We have described in detail the composition and structure as well as seasonal patterns of leaf area index and aboveground biomass in the E. miniata E. tetrodonta open forests of the Gunn Point regi on near Darwin in the Northern Territory of Australia. In all, 29 tree spec ies from four phenological guilds were recorded in these forests. Stand str ucture suggests that the forests were still recovering from the impacts of cyclone Tracy and subsequent frequent fires. Eucalyptus miniata and E. tetr odonta were significant contributors to overstorey leaf area index and stan ding biomass (> 70%), and both leaf area index and biomass were strongly co rrelated to basal area. Leaf area index was at a maximum (about 1.0) at the end of the wet season and declined over the dry season by about 30 40%. Th ere were proportionally greater changes in the understorey reflecting the g reater contribution of deciduous and semi-deciduous species in this strata. Standing biomass was about 55 t ha(-1). Detailed descriptions of leaf area index and biomass are important inputs into the development of a water and carbon balance for the savanna's of northern Australia.