The numerical investigation of air humidity effects on the fire spread in forests (case study: Malekrod-Siahkal forest)

Forest fires are a natural part of the ecosystem, but their uncontrolled spread can result in severe economic and environmental damage. Therefore, it is vital to take measures to prevent and manage their spread. However, given the intricate and complex nature of fires, studying real fires in their environmental context can be challenging, if not impractical. As an alternative, researchers can use computer simulation models based on field studies to better understand fire behavior and its effects on the environment. The FARSITE simulator, based on the Rothermel model, was used to conduct numerical simulations of fire spread with respect to fuel, topography, and weather conditions such as humidity. Simulation results showed that the Sorensen and kappa coefficients were at their highest at 0.80 and 0.77, respectively, in air humidity scenarios; with average values of fire spread rate, flame length, and fireline intensity being 0.58 m/min, 0.54 m, and 74.54 kW/m, respectively. Based on these results, it can be concluded that increasing air humidity is a natural way to prevent fire spread. Furthermore, numerical studies and simulations of fire behavior and spread are appropriate alternatives to experimental studies in this field due to their lower costs and fewer limitations.