抚育间伐对西山林场侧柏林冠层可燃物特征及潜在火行为的影响  

Effects of thinning on canopy characteristics and potential crown fire behavior of Platycladus orientalis in Xishan Forest Farm of Beijing

作　　者：高敏[1] 任云卯 周晓东 陈思帆 高钰 王会娟 顾泽 刘晓东[1,3] Gao Min;Ren Yunmao;Zhou Xiaodong;Chen Sifan;Gao Yu;Wang Huijuan;Gu Ze;Liu Xiaodong(Key Laboratory for Forest Resources and Ecosystem Processes,Beijing Forestry University,Beijing 100083,China;Beijing Xishan Experiment Forest Center,Beijing 100000,China;Emergency Management Department Key Laboratory of Forest Grassland Fire Risk Prevention and Control,Beijing 102202,China)

机构地区：[1]北京林业大学森林资源生态系统过程北京市重点实验室,北京100083 [2]北京市西山试验林场管理处,北京100000 [3]森林草原火灾风险防控应急管理部重点实验室,北京102202

出　　处：《北京林业大学学报》2022年第8期56-65,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】研究不同间伐强度对北京西山试验林场侧柏林冠层可燃物特征及其潜在火行为的影响,为冠层可燃物调控和预防高能量连续型树冠火的发生提供参考。【方法】以北京西山试验林场侧柏为研究对象,设置3种间伐强度(低15%、中35%、高50%,均为株数强度)的处理,并设置对照样地,每种处理设置3块重复样地。基于标准枝法所调查冠层可燃物参数(枝条数量、长度、基径),对冠层可燃物载量建立线性回归模型,进一步计算冠层容积密度。通过单因素方差分析探讨不同间伐强度对冠层可燃物特征(冠层可燃物载量、冠层容积密度)的影响。利用Behave Plus 5.0软件,分别根据样地可燃物含水率和气象条件设置中度湿度条件和10 m高空风速(0~18 m/s),探讨不同间伐强度对树冠潜在火行为指标(树冠火蔓延速率、火线强度、火焰长度、单位面积发热量等)的影响,并依据树冠火转化模型研究抚育间伐对连续型树冠火发生的影响。【结果】(1)林分冠层可燃物特征在不同间伐强度下存在差异,中度间伐强度下与未间伐样地差异最显著,冠层可燃物载量、冠层容积密度随着间伐强度的增加而减少,冠层可燃物载量由3.280 kg/m^(2)减少到0.540 kg/m^(2),冠层容积密度由0.478 kg/m^(3)减少到0.056 kg/m^(3)。(2)不同间伐强度下林分冠层可燃物载量、冠层容积密度垂直分布特征为随树高的增加而先增加后减少。(3)树冠潜在火行为指标在中度间伐强度下与未间伐样地差异显著,其中火线强度、火焰长度以及单位面积发热量随间伐强度的增大而减小,树冠火蔓延速率在抚育间伐后小于未间伐样地,但不随间伐强度的变化而变化,临界树冠火蔓延速率随间伐强度的增大而增大。在未间伐、低度间伐强度下样地将发生连续型树冠火,中度、高度间伐强度样地不发生;随着间伐强度增大,发生连续型树冠火时所[Objective]This paper aims to explore the effects of different thinning intensities on canopy fuel characteristics and potential crown fire behavior of Platycladus orientalis in Xishan Experimental Forest Farm in Beijing,so as to provide reference for the regulation of canopy fuel and the prevention of highenergy active crown fire.[Method]Taking Platycladus orientalis in Xishan Experimental Forest Farm in Beijing as the research object,three thinning intensities(low,15%;moderate,35%;high,50%)and the control were set up,and three repeated sample plots were set for each thinning intensity.Based on the canopy fuel parameters(branch number,length,base diameter)obtained by the standard branch method,a linear regression model was established for canopy fuel load,and the canopy bulk density was further calculated.The effects of different thinning intensities on canopy fuel characteristics(canopy fuel load and canopy bulk density)were discussed by single factor analysis of variance(ANOVA).Using BehavePlus 5.0software,according to the fuel moisture content and meteorological conditions of the sample plots,the humidity condition and 10 m high altitude wind speed(0-18 m/s)were set to explore the effects of different thinning intensities on the potential crown fire behavior indexes(crown fire spread rate,fire line intensity,flame length,calorific value per unit area,etc.).According to the crown fire transformation model,the effect of thinning on the occurrence of active crown fire was further studied.[Result](1)The characteristics of canopy fuel in different thinning intensities were different and the difference was the most significant between moderate thinning and control.Canopy fuel load and canopy bulk density decreased with the increase of thinning intensity,the former decreased from 3.280 to 0.540 kg/m^(2) and the latter decreased from 0.478 to 0.056 kg/m^(3).(2)After thinning with different intensities,the canopy fuel load and canopy bulk density distribution increased at first and then decreased with the increase of

关 键 词：侧柏林 抚育间伐 冠层可燃物 冠层容积密度 潜在火行为 

分 类 号：S791.38[农业科学—林木遗传育种]