Tree Species Vulnerability to Fire Increases at Dry Range Edge

Abstract

ABSTRACT Plant responses to fire are generally characterized for individual species and thus do not capture the variation in responses that can occur geographically. Here, we examine post‐fire responses across the climatic range of multiple resprouting eucalypt species following the 2019/20 Australian fire season. We found that two species exhibited higher rates of tree mortality, topkill (death of above‐ground biomass), and lower rates of seedling recruitment at the dry edge of their ranges (mortality up to 16% more likely, topkill up to 19% more likely, seedling recruitment an order of magnitude lower). However, one species maintained resilience (low rates of mortality and topkill and high rates of recruitment) across its range. We further find that most, but not all, species show elevated topkill—but not necessarily elevated mortality—in the largest trees, partially explained by pre‐fire stem damage. This divergence suggests many large trees survive fire through basal resprouting alone, effectively resetting canopy structure to a smaller size class rather than escaping disturbance impacts altogether. These results highlight the need for a more nuanced approach to classifying plant responses to fire that accounts for localized variation in plant responses. We suggest that classification of plant response to fire will be improved by including attributes such as plant size, disturbance regime, and climate. Such an approach is critically important for fire management and conservation planning.