Resistance vs resilience: Alternative mechanisms to survive severe cyclones in Australian tropical rainforest tree species

Ecological theory suggests that there is a trade-off between plant traits that enhance survival and those that enhance growth. The trade-off between safety (resistance) and growth (resilience) was investigated among tropical rainforest tree species in North Queensland, Australia, by examining damage and recovery following a severe cyclone. We classed individuals in six species into damage categories (no damage, severe branch damage, snapped, uprooted) in sites located in heavily impacted areas of three rainforest fragments on the Atherton Tablelands. Wood density and growth rate, characterized as mean total biomass accumulated, mean biomass per unit size (diameter at breast height), and mean rate of biomass accumulation were estimated in all species. Species differed in damage patterns sustained by the cyclone. We found a significant negative correlation between species wood density and (1) percent of individuals with snapped stems; and (2) percent of individuals with snapped stems or severe branch damage. This supports similar findings that suggest that high wood density is associated with greater ability to resist cyclone damage. A negative relationship was also found between wood density and each of the three biomass accumulation variables used to assess growth rate, suggesting that high wood density translates to a reduction in a tree’s ability to accumulate biomass post-disturbance. Collectively, these findings support the existence of a trade-off between resistance and resilience and confirm that the position of a species along that spectrum can be predicted by wood density.