Leaf size and shape interact to control flammability: An experiment with artificial leaves cut from the large-leaved species Sapranthus palanga

Climate change is altering fire regimes globally, increasing the occurrence, frequency, and severity of wildfires in ecosystems not traditionally adapted to fire, including tropical forests. Understanding the flammability of living plant tissues, particularly leaves—the most abundant and easily ignitable plant fuel—is crucial for predicting fire behavior and ecosystem responses. Leaf morphological traits such as size, shape, thickness, and surface area influence key physical processes like heat transfer, drying rate, and flame propagation, but their independent effects remain poorly understood due to confounding biochemical factors. To isolate the role of leaf size and shape in flammability, we performed controlled laboratory experiments using artificial leaves cut from a single large-leaved tropical species, Sapranthus palanga, thereby standardizing chemical composition and venation. The dataset comprises three experiments: (1) a control assessing differences between intact and cut leaf margins, (2) a factorial experiment testing the interaction between leaf shape (circular, rectangular, triangular) and size (small, medium, large), and (3) a shape-only experiment controlling for surface area. Measured variables include ignition time, flame duration, distance burned, and burning rate under standardized flame exposure. This dataset includes three files with the measured values for flammability as a function of size, shape, and the control dataset for our pilot study. These data provide a rigorous empirical foundation to understand how fundamental geometric leaf traits influence flammability, contributing to improved fire ecology models and management in tropical ecosystems facing changing fire regimes.