Coupling duff development with tree litter and downed fuel inputs, decomposition, and fire consumption in a long-term prescribed fire experiment in Florida

Background Mapping surface (i.e., litter and downed woody debris) and ground fuels (i.e., duff) is key to predicting fire behavior, consumption, emissions, and effects. Remote sensing effectively describes tree canopy attributes, but it is less effective to characterize surface and ground fuels because they are partially obscured by vegetation. Aims We mapped duff loads by leveraging the coupled relationship existing between canopy, surface, and ground fuels: canopy fuels provide the source material for the surface fuels which, along with the belowground root inputs, serve as the source material for duff formation. Methods We mapped annual surface fuel production from mostly tree components that contribute to duff formation using airborne laser scanning data. We adjusted a forest soil organic carbon model to simulate duff development under environmental factors that constrain decomposition and included consumption rates that accounted for fuel removal during prescribed burning. We tested the workflow in pine flatwoods in the southeastern US, where a long-term prescribed burning experiment has been running since 1958. Key results Comparison between modeled duff estimates, and field observations provided good agreement showing low bias and high coefficient of determination. Conclusions This approach allows surface and ground fuels to be mapped at high spatial resolution (≤5m) using aerial laser scanning. Implications This integrated modeling workflow improves upon current methods to describe heterogeneous duff layers and shows that surface and ground fuels can be mapped using remote sensing and ecological modeling.