Study On Fire Behavior In Mixed Fuel Complexes Of Korean Pine And Mongolian Oak Under No-wind And Zero-slope Conditions

Burning experiments with surface fuels collected from Korean Pine and Mongolian Oak mixed stand were conducted inside lab under no wind and zero slope conditions with controlled moisture content, fuel load and mixture ratio. Rate of spread, residual time, reaction intensity, fireline intensity and flame length were measured or deduced form the experiments. The results were compared with those computed using extended Rothermel model to test the performance of the model for this fuel type, especially for the effects of two different weighting methods for mixed fuels. The monomer weighted model gives the differences of the two fuels in mixed fuel. The results show that1) moisture content were significantly correlate with all fire behavior indicators and negative except residual time; fuel loading were significantly positive correlate with most fire behavior indicators but residual time was not significant; mixing ratio were negatively correlate with all fire behavior indicators except residual time2) the mean absolute errors of the above five fire behavior measurements were0.037m·min-1,77kW·m-2,15.5s,17.21kW·m-1and9.7cm, respectively and the mean relative errors of these variables were16%,22%,55.5%,48.5%and24%, respectively. The predicted residual time, fireline intensity and flame length were lower than the observed ones. These errors can be regarded as the lowest error for application of the extend Rothermel model in similar fuel types in field, which can provide valuable information for using the model to predicted fire behavior.3) Generally speaking, the two different weighting methods in Rothermel model did not show significant difference in the predictions of fire behavior for the mixed fuels experimented with here. When the ratio of Korean Pine needles was high, better prediction of rate of spread and reaction intensity were obtained using the surface area weighting method while better prediction of fireline intensity and flame length achieved using the load weighting method. When the ration of Korean Pine needles was low, the contrary results occurred. The importance of differences of the two direct weighted models was not great except residual time.