兴安落叶松针叶床层火蔓延的模拟

以黑龙江省帽儿山地区典型森林类型兴安落叶松林地表可燃物为研究对象,分析不同可燃物含水率、可燃物载量、风速和坡度与火蔓延速度之间的关系,共进行4(可燃物载量)×4(可燃物含水率)×3(风速)×3(坡度)=144组点烧试验,并建立适用于兴安落叶松针叶林的火蔓延模型。结果表明:在试验设定范围内,可燃物床层在火蔓延过程中80%为阴燃,火蔓延速度在75%区间内不超过6 m·h^-1,最大值为93.02 m·h^-1、最小值为0.41 m·h^-1;可燃物载量对火蔓延速度影响不显著,3个显著变量对火蔓延速度的影响由大到小的顺序为:风速、可燃物含水率、坡度;4个因子交互作用对火蔓延速度的相对贡献为:可燃物含水率×坡度×风速27.73%、风速17.22%、可燃物含水率×坡度×风速×载量13.01%、可燃物含水率×风速11.01%、坡度×风速9.21%;火蔓延速度预测模型的标准估计误差值为8.56,验证误差值为12.93。因此,在森林火行为预报工作中,应注意可燃物的特征、所处的地理位置及其环境因素。

Simulation of Fire Spread in Coniferous Bed of Larix gmelinii

With the surface fuel of Dahurian larch(Larix gmelinii), a typical forest type in Maoershan region, Heilongjiang Province, we studied the relationship between the different fuel moisture content, fuel load, wind speed, slope and the spreading speed. A total of 4(fuel load)×4(fuel moisture content)×3(wind speed)×3(slope) of 144 burn tests were conducted, and a fire spread model suitable for L. gmelinii forest was established. Within the experimental setting range, 80% of the fuel bed structure was smoldering during the spreading process, and the spreading speed was not more than 6 mh^-1 under the 75% interval with the maximum and minimum values of 93.02 and 0.41 mh^-1, respectively.The effect of fuel load on the spreading speed is not significant, and the effects of three significant variables on the spreading speed are in the descending order of wind speed,fuel moisture content and slope. The relative contribution of the interaction of the four factors to the spreading speed in the descending order was fuel moisture content×slope×wind speed 27.73%, wind speed 17.22%, fuel moisture content×slope×wind speed×fuel load 13.01%, fuel moisture content×wind speed 11.01%, and slope×wind speed 9.21%. The standard estimation error value for establishing the spreading speed prediction model was 8.56, and the verification error was 12.93. Therefore, the characteristics, geographical location and environmental factors of combustible materials should be paid attention to forest fire behavior prediction.