林分尺度上的森林火灾风险评估方法及应用

Method and Application of Forest Fire Risk Assessment on Forest Stand Scale

[目的]基于森林燃烧概率、潜在火行为和火影响评估一个区域的森林火灾风险是有效开展林火管理的基础。[方法]利用森林燃烧概率模拟软件(Burn-P3)模拟了北京九龙山林场的燃烧概率、潜在火强度、蔓延速度及火发生类型。根据林场内各林班的生态重要性、生态脆弱性和保护等级确定火影响,并考虑火对周围城镇和水源的潜在影响,利用层次分析方法建立了林分尺度上的森林火灾风险评估体系。[结果]结果表明,研究区的平均燃烧概率为0.0351,燃烧概率高和很高的区域分别占研究区的10.3%和6.0%。火烧以地表火和间歇性树冠火为主,平均火强度及蔓延速度分别为2140.9 kW·m^(-2)和3.7 m·min^(-1)。火行为指数高和很高的区域分别占17.8%和14.0%。[结论]研究区森林生态价值和火对环境的影响较高。森林火灾风险评估结果显示,火灾风险高和很高的区域占31.8%。西部、北部及南部的落叶松林和混交林的火灾风险较高,未来需要加强针对性的林火管理。

[Objective]To study the forest fire risk assessment based on the burn probability,fire behavior,and po-tential fire impact.[Method]The Burn-P3 model was used to simulate the burn probability,potentialfire intensity,fire spread,and fire type in the Jiulongshan Forest Farm.The fire impact was calculated from ecology importance,vulnerability,and protection level of each forest stand.The exposure indicated the impacts of fire on urban and water resources.The forest fire risk assessment system on forest farm scale was established by using analytic hierarchy pro-cess(AHP).[Result]The results showed that the average burn probability was 0.0351 for the forest stand area,and the areas with high and very high burn probability accounted for 10.3%and 6.0%,respectively.The fire types are sur-face fire and intermitted crown fire.The average fire intensity and rate of spread were 2140.9 kW/m2 and 3.7 m/min,respectively.The areas with high and very high fire behavior index accounted for 17.8%and 14.0%,respectively.[Conclusion]The ecological value and potential fire impact of the forests are relative high and the fire risk assess-ment will be helpful to enhance the fire management.The fire risk assessment shows that the areas with high and very high fire danger rating account for 31.8%.The deciduous coniferous forest and mixed forest in west,north,and south parts of the farm show the higher fire risk,fire management activities should be strengthened for the purpose of risk mitigation.