Abstract:
Roughly 3% of the Earth’s land surface burns annually, representing a critical exchange of energy and
matter between the land and atmosphere via combustion. Fires range from slow smouldering peat
fires, to low-intensity surface fires, to intense crown fires, depending on vegetation structure, fuel
moisture, prevailing climate, and weather conditions. While the links between biogeochemistry,
climate and fire are widely studied within Earth system science, these relationships are also mediated
by fuels—namely plants and their litter—that are the product of evolutionary and ecological
processes. Fire is a powerful selective force and, over their evolutionary history, plants have evolved
traits that both tolerate and promote fire numerous times and across diverse clades. Here we outline a
conceptual framework of how plant traits determine the flammability of ecosystems and interact with
climate and weather to influence fire regimes. We explore how these evolutionary and ecological
processes scale to impact biogeochemical and Earth system processes. Finally, we outline several
research challenges that, when resolved, will improve our understanding of the role of plant evolution
in mediating the fire feedbacks driving Earth system processes. Understanding current patterns of fire
and vegetation, as well as patterns of fire over geological time, requires research that incorporates
evolutionary biology, ecology, biogeography, and the biogeosciences.
