八达岭林场油松林冠层可燃物特征及潜在火行为  

Characteristics and potential fire behavior of combustibles in the canopy of Pinus tabuliformis forest in Badaling Forest Farm of Beijing

作　　者：陈敏斯 杜建华 王薇 于海晨 王博[1] 顾泽 刘晓东[1] Chen Minsi;Du Jianhua;Wang Wei;Yu Haichen;Wang Bo;Gu Ze;Liu Xiaodong(School of Nature Conservation,Beijing Forestry University,Beijing 100083,China;Forest Fire Prevention Early Warning and Monitor Center of Ministry of Emergency Management,Beijing 100055,China)

机构地区：[1]北京林业大学生态与自然保护学院,北京100083 [2]应急管理部森林防火预警监测信息中心,北京100055

出　　处：《北京林业大学学报》2022年第3期55-64,共10页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(31770696)。

摘　　要：【目的】研究冠层可燃物特征和树冠火发生条件,模拟潜在火行为特征,对于森林可燃物管理及树冠火有效防控均具有重要意义。【方法】本文以北京市八达岭林场油松林为研究对象,利用破坏性取样方法,选择具有代表性的18株油松样木进行采伐,自第一活枝高始,以1 m为一个层次对油松林冠层由下而上进行划分,不足1 m的按照1 m层次划分,并按照冠层可燃物枝条径阶大小(针叶;大枝直径≥0.64 cm;小枝直径<0.64 cm)调查冠层总可燃物生物量,结合样地面积和油松林平均冠长,计算样地平均冠层可燃物负荷量(CFL)和冠层容积密度(CBD)。基于林分因子,建立与林分结构参数(胸径、第一活枝高、冠长、树高、冠幅)的多元回归模型;根据冠层可燃物负荷量模型可估算样地平均冠层容积密度,结合研究区防火期内月平均最大风速和地表可燃物负荷量,在3种细小可燃物含水率条件下(6%、10%、14%),利用van Wagner和Cruz的树冠火蔓延模型,预测油松林树冠火的发生,利用Byram模型计算冠层潜在火行为特征(如火线强度和火焰高度)。【结果】(1)油松林平均冠层可燃物负荷量为4.54 t/hm^(2),冠层容积密度为0.21 kg/m^(3),可燃物负荷量分布呈现由下而上逐层递减的趋势。林冠底层(0~1 m)可燃物占冠层总可燃物比例最大,为54.03%,大枝在林冠底层分布比例较大且快速逐层递减,针叶在各层次均有较大比例分布。(2)基于林分因子建立的冠层可燃物负荷量非线性模型具有较高的拟合度,其中胸径和第一活枝高与冠层可燃物负荷量呈极显著相关(P<0.01),在不破坏林木的情况下,根据林分易测因子可较好地估测油松林冠层可燃物负荷量。(3)在低燃烧条件下,除4月份外油松林发生间歇型树冠火的概率均低于0.5;在中度燃烧条件下,春季(3−5月份)风速较大,均存在发生连续型树冠火的可能;在极端干燥的高燃烧条件�[Objective]Canopy fire is a type of high-energy fire which severely damages forest resources.It is difficult to extinguish and threatens the safety of fire fighting personnel.Analyzing the characteristics of canopy combustibles and the occurrence conditions of canopy fires,and simulating potential fire behavior characteristics are of great significance for forest combustibles management and effective prevention and control of canopy fires.[Method]The study took the Pinus tabuliformis forest in the Beijing Badaling Forest Farm as the research object.Using destructive sampling methods to harvest 18 representative samples of P.tabuliformis,starting from the first living branch height,the canopy of the P.tabuliformis forest was divided from bottom to top with 1 m as a level,those less than 1 m were divided into 1 m level,and investigated the total biomass of combustibles in the canopy according to the diameter of the canopy combustible branches(needles;bough diameter≥0.64 cm;twig diameter<0.64 cm),which combined the plot area and the average canopy length of the P.tabuliformis forest to calculate the canopy fuel load(CFL)and canopy bulk density(CBD).Based on stand factors,we established a multiple regression model with stand structure parameters(DBH,height of the first living branch,crown length,tree height,crown width);estimated the sample plot based on the canopy fuel load model.Under the conditions of three fine combustibles moisture content(6%,10%,14%),the average CBD,combining with the average monthly maximum wind speed and the surface fuel load in the study area,the canopy fire spread rate model of van Wagner and Cruz was used to predict the occurrence of canopy fire in the P.tabuliformis forest,and the Byram model was used to simulate potential fire behavior characteristics(such as the intensity of the fire line and the height of the flame).[Result](1)The average canopy fuel load of P.tabuliformis forest was 4.54 t/ha,the CBD was 0.21 kg/m^(3),and the fuel load distribution was gradually decreasing from bott

关 键 词：油松 冠层可燃物负荷量 冠层容积密度 树冠火 火行为 

分 类 号：S762.1[农业科学—森林保护学]