Live fuel moisture and wildland fire behaviour

Abstract

Live fuel moisture content (LFMC) is a parameter that affects the flammability of plants, and the capacity to measure it remotely makes it an accessible variable for use in fire behaviour models. Although the effect of LFMC on the flammability of fuel particles has clear theoretical support however, the way in which this relates to fire behaviour is complex and difficult to quantify so that empirical studies of heath and forest fires at times yield weak or ambiguous results. This study examines the way in which moisture affects fire behaviour by using a process-based conceptual framework (Zylstra 2011) to identify feedbacks and complexities that may confound empirical analysis. Z11 links empirically-derived sub-models of flammability characteristics within a dynamic physical framework where heat is transferred convectively across spaces between leaves, branches, plants and plant strata. The ignitability, combustibility and sustainability of flame from burning leaves interacts with the geometry of the fuel array to determine whether flame will spread across horizontal spaces affecting rates of spread, and vertical spaces affecting flame heights.[1]