Cyclone effects on the structure and production of a tropical upland rainforest : implications for life-history tradeoffs

Wind is known to alter the structure and functioning of forest ecosystems. Because the intensity and frequency of severe wind events are likely to increase, it is important to understand the species- and substrate-specific effects of these disturbances. We assessed the structure and production among 63 species of trees in an Australian tropical rainforest before and after Cyclone Larry (March 2006). We assessed forest occurring on two different substrates: nutrient-poor schist and relatively nutrient-rich basalt. Leaf area reduction and stem breakage were markedly variable among species, but were more evident on basalt soils than schist soils, and were positively correlated with leaf N and P. In the 18-month period following the cyclone, litterfall, stem biomass increment, and ANPP were 44, 20, and 27% of pre-cyclone measurements and did not differ between soils. More severe modification of leaves, branches, and stems on basalt soils, relative to schist soils, suggests that trees/species growing on nutrient-limited soils are less susceptible to high winds. Disturbance regime and resource availability are likely to interact, creating potential plant strategies that increase fitness either by enhanced investments in carbon or enhanced investments in nitrogen and phosphorus.