Study On Fire Behavior Of Fuel Bed Of Mongolian Oak Broadleaf Under No-wind And Zero-slope Conditions

Fuel beds composed of Mongolian oak leaves collected from secondary Mongolian oak stand were constructed with varied fuel moisture, loading and depth. Totally 100 experimental fires with these fuel beds were burned inside laboratory under no-wind and zero-slope conditions. The results indicate that rates of spread of fuel beds of Mongolian oak leaves are slower than 0.5 m·min-1. Fuel moisture, fuel bed depth and fuel load significantly influence fire spread. The effect of fuel moisture on fire spread is not affected by fuel bed depth and loading while that of fuel bed depth is influenced by fuel bed load. The effect of fuel load on rate of spread is not so clear and needs further exploitation. Packing ratio dose not exert much influence on fire spread of the fuel bed.A spread model was established for this fuel type with fuel moisture, fuel load and fuel bed depth as predictive variables. The model can account for 83% variance of rate of spread of Mongolian oak leaves with mean absolute error of 0.041 m·min-1 and mean relative error less than 17%. Fuel moisture, fuel bed depth and fuel load significantly influence flame height, residence time and reaction, it the fuel moisture on influencing fire behavior is any relationship with fuel load and fuel bed height, but fuel and fuel bed height are influencing each other on influencing fire behavior. It is better that established active model with fuel moisture, fuel bed depth and fuel load than other factors, mean absolute error of active flame height model is 6.174cm. and the mean relative error is 20.3%. Mean absolute error of active residence time is 0.182min, and the mean relative error is 18.9%. Mean absolute error of active reaction efficiency is 0.085, and the mean relative error is 17.4%.There is significant correlation between fire spread rate and flame height, residence time and reaction efficiency, and the correlation between flame height and residence time and reaction efficiency is also significant, when the value of a factor increase, the value of another factor which corresponding with it is also increase.