大兴安岭根河雷击火干扰后地表死可燃物负荷及影响因子

Surface Dead Fuel Load and Influencing Factors After Lighting Fire Disturbance in Genhe of Daxinganling

本研究以内蒙古根河林区内兴安落叶松(Larix gmelinii)雷击火迹地为研究对象,调查林地内死可燃物分布和环境因子,分析不同程度(轻度、重度)雷击火干扰后地表1、10、100 h时滞死可燃物负荷量和总负荷量的动态变化,探讨地表死可燃物负荷量的具体影响因素。结果表明,(1)1、10、100 h时滞死可燃物负荷量和总负荷量均表现为轻度火烧>重度火烧,10年的恢复期内,轻度火烧样地内地表死可燃物负荷量恢复到与对照样地接近的水平,而重度火烧样地依然与对照样地差异显著。(2)1、10、100 h时滞可燃物负荷量均与郁闭度和胸径存在明显的正相关关系(P<0.05),而与火烧程度存在明显的负相关关系(P<0.05),坡位对可燃物负荷量有一定程度影响,但不显著。(3)采用逐步回归法,建立地表死可燃物负荷量与影响因子的多元估测模型,其中1 h可燃物负荷量模型精度最低,r^(2)=0.519,误差最大。10 h可燃物负荷量模型精度最高,r^(2)=0.758,误差最小。100 h可燃物负荷量模型r^(2)=0.726,总负荷量模型r^(2)=0.658,除1 h可燃物负荷量模型精度较低外,其他模型的模拟精度>65%,可以进行推广与应用。研究结果可以探究该地区再次发生火灾的可能性,以期为大兴安岭林区雷击火的发生、预防预警提供科学依据。

This research takes the lightning strikes of Larix gmelinii in Genhe forest area of Inner Mongolia as the research object,to investigate the distribution of dead combustibles and environmental factors in the forest land,analyze the dynamic changes of the dead combustibles load at 1 h,10 h,and 100 h time-lag and total load after the disturbance of lightning fires of different degrees(mild and severe),and explore the surface specific influencing factors of dead combustible load.The results showed that:(1)1 h,10 h,100 h time-lag combustibles load and total load were all shown as mild fire>severe fire.During the ten-year recovery period,the surface dead combustible load in the mildly burned plot recovered to a level close to that of the control plot,while the severely burned plot was still significantly different from the control plot.(2)The 1 h,10 h,and 100 h time-lag combustible load were all significantly positively correlated with canopy closure and breast diameter(P<0.05),while there was a significant negative correlation with the degree of fire(P<0.05).The slope position had a certain degree of influence on the combustible load,but it was not significant.(3)The stepwise regression method was used to establish a multivariate estimation model of the surface dead combustible load and the impact factor.The 1 h combustible load model had the lowest accuracy,r^(2)=0.519,and the largest error.The 10 h combustibles load model had the highest accuracy,r^(2)=0.758,and the smallest error.The 100 h combustibles load model r^(2)=0.726,and the total load model r^(2)=0.658.Except for the 1 h combustibles load model with lower accuracy,the simulation accuracy of other models was>65%,which could be promoted and applied.The research results can explore the possibility of fires in this area again,in order to provide a scientific basis for the occurrence,prevention and early warning of lightning fires in the Daxinganling.