The Role of Bulk Density and Leaf Morphology in Litter Flammability

Abstract

Litter flammability is a key factor in fire behavior prediction and management, particularly in ecosystems with frequent fire regimes. While numerous studies have examined the physical, morphological, and chemical traits influencing flammability and have speculated about the relative importance of each factor, few have isolated the effects of bulk density and leaf morphology on fire dynamics or performed other mechanistic studies. This research investigates how these factors contribute to litter combustion by standardizing leaf shape and size across four Quercus species while measuring key fire behavior metrics, including flame height, burn duration, temperature variation, and mass loss. Results indicate that bulk density plays a significant role in flame height and mass loss and has a lesser, but not negligible impact on flame duration and max temperature. Each species responded similarly but each to a different degree in response to equal changes in bed height and bulk density, indicating bulk density has a non-linear effect on flammability characteristics. These findings underscore the importance of considering inherent leaf traits alongside bulk density when predicting fire behavior and informing fire management.