Pinus koraiensis plantation has high fire risks due to high oil content in branches and leaves. The spread of surface fire is the main way of forest fire expansion. Understanding the surface fire spread rate can provide scientific guidance for fire fighting. We carried out a laboratory experiment with surface fuel of Pinus koraiensis plantation in Maoershan area of Heilongjiang Province. We set different levels of fuel moisture contents (5%, 15%, 25%), fuel loads (0.5, 0.7, 0.9, 1.1 kg·m-2), and slope (0°, 10°, 20°, 30°, 40°) to simulate the characteristics of fuel bed in the field, and quantified the spread rate by thermocouple method. We further compared and analyzed the prediction accuracy of Rothermel model, modified Rothermel model and random forest model, and evaluated the optimal model for predicting the surface fire spread rate of P. koraiensis plantation. The results showed that the overall efficacy of directly using the Rothermel model to predict the surface fire spread rate of P. koraiensis plantations was good, but the prediction result of the spread rate under the conditions of high slope and high moisture content was not satisfied. The Rothermel model after refitting the slope parameters and the random forest model had good prediction efficacy and similar prediction accuracy. The random forest model needed to be further evaluated and verified due to its own characteristics. The modified Rothermel model was more suitable for predicting the surface fire spread rate of P. koraiensis plantations at a slope range of 0°-40° than the others.
红松人工林因其枝叶内油脂含量较高而具有极高的火灾风险,地表火蔓延是其火灾扩展的主要方式,研究地表火蔓延速率预测模型可以为红松人工林的火灾扑救工作提供科学指导。本研究以黑龙江省帽儿山地区红松人工林地表可燃物为研究对象,设置不同的可燃物含水率(5%、15%、25%)、载量(0.5、0.7、0.9、1.1 kg·m-2)和坡度(0°、10°、20°、30°、40°),模拟野外可燃物床层特征进行室内点烧试验,使用热电偶法测定蔓延速率,根据实测蔓延速率对比分析Rothermel模型、修正后Rothermel模型和随机森林模型的预测精度,评估预测红松人工林地表火蔓延速率的最优模型。结果表明:直接使用Rothermel模型预测红松人工林地表火蔓延速率整体效果较好,但对于高坡度、高含水率条件下的蔓延速率预测效果不理想。重新拟合坡度参数后的Rothermel模型与随机森林模型预测效果均较好,且预测精度相近,但随机森林模型因其本身特性,还需进一步进行评估和验证。修正后的Rothermel模型更适合预测0°～40°坡度下的红松人工林地表火蔓延速率。.
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