林火干扰对广东省桉树林生态系统碳密度的影响

林火作为森林非连续的生态因子,引起森林生态系统碳库碳储量与碳分配的变化,影响森林演替进程及固碳能力。以桉树林不同林火干扰强度的火烧迹地为对象,采用相邻样地比较法,以野外调查采样与室内试验分析相结合为主要手段,研究不同林火干扰强度对森林生态系统各碳库及生态系统碳密度变化和空间分布格局的影响,探讨林火干扰对生态系统碳密度与碳分布格局的影响机制。结果表明:林火干扰降低了植被碳密度(P<0.05),轻度、中度和重度林火干扰样地植被碳密度依次为67.88、35.68和15.50 t·hm^-2,相比对照分别下降了15.86%、55.78%和80.79%;在轻度、中度和重度林火干扰样地中,凋落物碳密度分别为1.43、0.94和0.81 t·hm^-2,相比对照分别降低了28.14%、52.76%和59.30%;不同林火干扰强度样地土壤有机碳密度均低于对照,且减少幅度随土壤剖面深度增加而逐渐变小,轻度、中度和重度林火干扰样地土壤有机碳密度分别为103.30、84.33和70.04 t·hm^-2,相比对照分别下降了11.67%、27....

Effects of forest fire on carbon density of Eucalyptus robusta forest ecosystem in Guangdong Province

As a non-continuous ecological factor,forest fire affects carbon pool and carbon distribution in forest ecosystems,and alters forest succession and carbon sequestration capacity.In this study,the burned sites of Eucalyptus robusta forests with different fire intensities were selected as the research object.A comparison method of adjacent plots was used in combination with field sampling and laboratory analysis,to investigate the effects of different forest fire intensities on the variation and spatial distribution patterns of carbon density of different ecosystem components in forest ecosystems.We found that forest fire reduced vegetation carbon density(P<0.05).Carbon density of vegetation in the plots with light,moderate and high fire intensities was 67.88,35.68 and 15.50 t·hm^-2,with a decrease of 15.86%,55.78%and 80.79%compared to that of the control,respectively.After interference of light,moderate and high forest fire intensities,carbon density of litter was 1.43,0.94 and 0.81 t·hm^-2,respectively,with a reduction of 28.14%,52.76%and 59.30%,respectively.Soil organic carbon density in forests with different forest fire intensities was lower than that of the control,and the reduction amplitude gradually became smaller with increasing soil depth.Soil organic carbon density of E.robusta forests was 103.30,84.33 and 70.04 t·hm^-2,respectively,which decreased by 11.67%,27.89%and 40.11%,respectively.In forests with light,moderate and high forest fire intensities,ecosystem carbon density was 172.61,120.95 and 86.35 t·hm^-2,respectively,which decreased by 13.53%,39.41%and 56.74%,respectively.In summary,forest fire disturbance reduced carbon density of E.robusta forests,which decreased with increasing forest fire intensity.Compared with the control,light-intensity forest fire interference had no significant effect on ecosystem carbon density(P>0.05),while moderate-and high-intensity forest fire interference had a significant effect on ecosystem carbon density(P<0.05).