Investigation of Fires in Natural Ecosystems of the Ukrainian Roztochchiya by Wildland Fire Dynamics Simulator Model

Abstract

Fires in natural ecosystems require a comprehensive approach due to the dependence of these processes on many factors -climatic conditions, moisture content of combustible material, type of ignition source, soil temperature regime, availability of possibilities and tools for extinguishing, presence of fire-fighting obstacles, organization of localization and elimination. The investigation of natural fires today takes into account (developed and effectively used) computer models, which are based on numerical methods of the physics of combustion of substances and materials. In the presented work, a study of the fire at the site was carried out, which included the growth of grass and other components of the phytocenosis, particularly shrubs. The research was carried out taking into account the environmental conditions and the combustible material's physical and chemical properties. In general, the fire simulation lasted 180 seconds. Rapid burning stopped 66 s from the beginning of ignition, and after that, single burning and smoldering of the studied area were observed. It was established that the maximum flame temperature was more than 1250 °C, which was observed in 33 s within the limits of burning grass in stacks. The maximum power from the fire of the studied area is reached approximately at the 65 th second and was 209650 kW/m 3 , and starting from the 66 th second, it was decreasing. It should be noted that the species composition of the pyrogenic succession is depleted, and on the site of the fire, there is a scattering of plants and a spontaneous arrangement in the studied area. The predominance of Asteraceae in the pyrogenic succession is a rather positive phenomenon because they are the most widespread family of the flora of Ukraine and have great practical applications and are used as medicinal, food, fodder, honey, oil, and decorative species.