A Stochastic Spatial Model for the Consumption of Organic Forest Soils in a Smoldering Ground Fire

A STOCHASTIC SPATIAL MODEL FOR THE CONSUMPTION OF ORGANIC FOREST SOILS IN A SMOLDERING GROUND FIRE Benjamin Victor Holt A spatial model for the consumption of organic forest soil (duff) by smoldering combustion is developed. Smoldering ground fires have an enormous impact upon the ecology and management practice of forest lands throughout the temperate zone. It is the goal of this effort to predict, and hence better understand, observed spatial patterns in duff consumption. Models of duff consumption are often empirically derived and consequently too specific to the site of study. Additionally, models of duff consumption based upon models of smoldering combustion are difficult to use and can yield questionable results since few, if any, models of smoldering combustion are created specifically for duff. This effort seeks to circumvent such shortcomings by creating a general duff consumption model that requires a small number of user-determined parameters that are easily estimated from field samples. These parameters include organic bulk density, moisture content, mineral content, and duff depth. The fuel-bed is modeled by a two-dimensional stochastically updated cellular automaton. Model output compares favorably to empirical and field studies concerning spatial aspects of duff consumption. Modifications to the model are proposed that would advance understanding of the ecological impact of duff consumption.