Fire Investigation via Analysis of Ignition Characteristics and Carbon Emissions of Fire–prone Surface Fuels in Korea

Abstract

This study focuses on the identification of ignition characteristics and carbon discharge resulting from combustion of surface fuels vulnerable to forest fire. Four withered surface fuels, including dead leaves and cones of Pinus densiflora, dead leaves of Quercus variabilis, and Castenea crenata burs; and six biofuel herbs, including Agsstache rugosa, Oplismenus undulatifolius, Pueraria thunbergiana, Cirsium japonicum var. ussuriense, Festuca ovina L., and Osmundaceae were selected for analysis. Also, monthly carbon emissions (Jun. - Oct. 2008) from Festuca ovina were analyzed. As a result of tests, it was confirmed that dead leaves and cones of P. densiflora and C. crenata burs were instantly ignited with flame, which lasted quite a while. The total CO2 and CO emissions from the 10 different kinds of surface fuels analyzed on this study were 28-98 g and 0.76-4.08 g per 50 g of each fuel, respectively, indicating that the amount of carbon emissions vary depending on the type of fuel. The results also demonstrated that there is a great difference between withered fuels and biofuels in terms of carbon emissions. More specifically, the four withered types of fuels, compared to the six biofuel herbs, were found to emit more CO2 and CO. In particular, dead cones of P. densiflora emitted more carbon dioxide (CO2) and carbon monoxide (CO) than the rest of the surface fuels. Also, the carbon emissions were found high during the period of from August to September. Consequently, in the case of a forest fire, dead cones and leaves of P. densiflora are expected to emit up to 3.5 times more CO2 and CO than the other surface fuels. The area covered with dead leaves and pine cones is thought to have a high risk of ignition, high fire inten- sity because of relatively long lasting flame, and rapid fire spread. Herbs and living fuels with high moisture content are expected to elucidate the course of fire in that they produce large amount of combustion prod- ucts such as smoke and carbon discharge resulting from nonflame-ignition.