北京西山可燃物特点及潜在火行为

Characteristics of Forest Fuel and Potential Fire Behavior in Xishan Mountain of Beijing

以北京西山魏家村林场为研究区域,通过样地调查和森林清查数据将可燃物划分为针叶林、阔叶林、混交林和疏林地。根据样地调查和树木生物量模型计算不同类型和不同层次的可燃物载量、厚度和高度。根据2000—2006年当地气象数据,确定历史平均最大风速的平均值和主风向,在此背景下对风场进行模拟,进而对地表火和树冠火进行模拟计算,计算出不同类型火发生时火蔓延速度、火强度和火焰高度的分布图。地表火的蔓延速度为0.01～0.22m.s-1,树冠火的蔓延速度为0.12～2.25m.s-1;地表火的火线强度为144～6595kW.m-1,树冠火的火线强度为3214～189002kW.m-1;地表火的火焰高度为0.37～2.50m,树冠火的火焰高度为1.75～13.4m。通过对可燃物和火行为指标的计算,可以为防火林带规划和防火林管理提供依据,也可为可燃物管理、扑火安全防范等提供借鉴。

In this paper, we studied the forest fuel and potential fire behavior in terms of average maximal wind speed derived from records in Weijiacun Forest Center from 2000 to 2006. The fuel types were classified into coniferous forest, broadleaf forest, mixed forest, and sparse forest based on forest inventory and sample plots. Vertical and horizontal distribution of the fuel was calculated from sample plots and tree biomass model, including fuel loading, thickness and height. Based on fuel distribution and wind simulation, fire spread rate, fire intensity, and flame height of surface fire and crown fire were calculated. The fuel loading was 81.93,57. 46,107.02 and 51.92 t · hm ^-2, and crown base height was 230.0, 200.0, 200. 0, and 280.0 cm respectively in coniferous forest, broadleaf forest, mixed forest, and sparse forest. Surface fire spread rate was 0.01 ～0.22 m · s^-1 , and crown fire spread rate was 0. 12 ～2.25 m · s^-1. Surface fire line intensity was 144 ～6 595 kW · m ^-1 , and crown fireline intensity was 3 214 ～189 002 kW · m^-1 Flame height of surface fire was 0.37 ～2.50 m, and flame height of crown fire was 1.75 ～ 13.4 m. All above quantitative data were crucial in fuel management and fire safety issues.