林火干扰对广东木荷林生态系统碳库的影响

Effects of forest fire disturbance on carbon pools of Schima superba forest ecosystem in Guangdong Province

森林碳库在调节CO_(2)浓度及减缓温室效应中发挥重要作用。选择广东木荷林为研究对象,通过相邻样地法,进行植被生物量、凋落物生物量和土壤样品的采样与分析,研究不同林火干扰强度对生态系统各碳库(植被、凋落物和土壤有机碳)及生态系统碳库产生的变化规律和空间分布格局及其影响因素。结果表明:(1)植被碳密度随着林火干扰强度增强而减少,但不同组分的植被碳密度表现不同,乔木碳密度在不同林火干扰强度下变化与植被碳密度变化一致,而草本碳密度则呈现相反的变化趋势。相同林火干扰强度下,植被各组分碳密度均以乔木层降低幅度最大。林火干扰均显著降低了凋落物碳密度(P<0.05),并随林火干扰强度的增加其降低幅度增大,但不同林火干扰强度对凋落物碳密度的影响有所差异。林火干扰降低了土壤有机碳密度,且降低幅度随土层深度增加而逐渐变小。(2)林火干扰有效改变了生态系统碳库的空间分布格局。对照样地木荷林土壤有机碳库占比为61.59%,重度林火干扰后,土壤有机碳库占比为70.96%呈上升趋势,占生态系统碳库的优势地位,而植被和凋落物碳库占比呈下降趋势,处于生态系统碳库的次要地位。(3)双因素方差分析表明,林火干扰强度和土层深度及其交互作用均对土壤有机碳密度有显著影响。林火干扰强度解释了土壤有机碳密度变异的8.78%,土层深度解释了土壤有机碳密度变异的70.29%,林火干扰强度和土层深度之间的交互作用解释了土壤有机碳密度变异的8.16%。研究发现:林火干扰降低了生态系统碳库,且随林火干扰强度增加,生态系统碳库减少幅度增大。轻度林火干扰对森林生态系统碳库的影响差异不显著,而中度和重度林火干扰对森林生态系统碳库的影响差异显著。研究结果对深化亚热带森林固碳效应的影响机制提供理论支撑。

Forest carbon pools play an important role in regulating CO_(2)concentration and mitigating the greenhouse effect.In this study,the Schima superba forest in Guangdong was selected as the research object.Through the adjacent plot method,the sampling and analysis of vegetation biomass,litter biomass and soil samples were conducted to study the impact of different forest fire disturbance intensities on the various carbon pools(vegetation,vegetation,litter and soil organic carbon)and the change law and spatial distribution pattern of ecosystem carbon pool and its influencing factors.The results showed that the vegetation carbon density decreased with the increase of forest fire disturbance intensity,but the vegetation carbon densities of different components were different.The change of tree carbon density under different forest fire disturbance intensities was consistent with the change of vegetation carbon density.The carbon density showed the opposite trend.Under the same fire disturbance intensity,the arbor layer had the largest decrease in the carbon density of each component of vegetation.The forest fire disturbance significantly reduced the litter carbon density(P<0.05),and the decrease range increased with the increase of the forest fire disturbance intensity,but the effects of different forest fire disturbance intensities on the litter carbon density were different.The forest fire disturbance reduced soil organic carbon density,and the reduction range gradually became smaller with the increase of soil depth.Forest fire disturbance has effectively changed the spatial distribution pattern of the ecosystem carbon pool.The proportion of soil organic carbon reservoir in the control plot was 61.59%.After severe forest fire disturbance,the proportion of soil organic carbon pool was 70.96%,showing an upward trend,accounting for the dominant position of ecosystem carbon pool,while the proportion of vegetation and litter carbon pool showed a downward trend,which was in the secondary position of ecosystem carbon pool.ANOVA showed that the intensity of forest fire disturbance and the depth of soil layer and its interaction had a significant impact on soil organic carbon density.The intensity of forest fire interference explained 8.78%of the soil organic carbon density variation,the soil layer depth explained 70.29%of the soil organic carbon density variation,and the interaction between the forest fire interference intensity and the soil layer depth explained 8.16%of the soil organic carbon density variation.The study found that forest fire disturbance reduced the ecosystem carbon pool,and as the intensity of forest fire disturbance increased,the reduction in ecosystem carbon pool increased.The impact of low forest fire disturbance on forest ecosystem carbon pool was not significant,while the impact of moderate and high forest fire disturbance on forest ecosystem carbon pool was significant.The research results provide theoretical support for the impact mechanism of deepening the carbon sequestration effect of subtropical forests.