兴安落叶松天然林不同碳库碳汇变化驱动因素的差异性  

Differences of driving factors for carbon sink changes in different carbon pools of Larix gmelinii natural forests

作　　者：梅雪松 陈冠谋 董灵波[1] MEI Xuesong;CHEN Guanmou;DONG Lingbo(Ministry of Education Key Laboratory of Sustainable Forest Ecosystem Management/School of Forestry,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]森林生态系统可持续经营教育部重点实验室/东北林业大学林学院,哈尔滨150040

出　　处：《应用生态学报》2024年第10期2639-2647,共9页Chinese Journal of Applied Ecology

基　　金：十四五国家重点研发计划项目(2022YFD2200502);黑龙江省头雁创新团队计划项目(森林资源高效培育技术研发团队)资助。

摘　　要：天然林生态系统内部乔木层的碳平衡过程受林木生长、枯损和进界3个碳库的共同影响,但各碳库碳汇量的动态变化过程及其驱动因素还不明确。为此,本研究以大兴安岭地区第七次和第八次310块国家森林资源连续清查数据为基础,利用逐步回归方法和结构方程模型评估生物因素(林分和多样性)和非生物因素(土壤、地形和气候)对兴安落叶松天然林林分生长量、进界量和枯损量3个碳汇动态过程的影响。结果表明:兴安落叶松天然林林分平均生长量、进界量和枯损量分别为0.73、0.17和0.41t·hm^(-2)·a^(-1);林分碳汇生长量随坡向指数(总路径系数β=0.135)、林分断面积(β=0.132)和坡位(β=0.085)的增加而增加,随林分平均年龄(β=-0.225)和海拔(β=-0.196)的增加而减小;进界量与林分断面积(β=-0.368)、林分平均年龄(β=-0.240)、土壤pH(β=-0.184)、土壤全磷(β=-0.115)和树种丰富度(β=-0.012)呈显著负相关,而与土壤全氮(β=0.258)呈显著正相关;对枯损量影响较大的因子依次为林分平均树高(β=0.276)>Simpson指数(β=0.232)>土壤全磷(β=0.195)>林分断面积(β=0.154)>土壤pH(β=0.084)。林龄、断面积和平均树高是林分碳汇生长量、进界量和枯损量最重要的影响因子,地形和土壤条件也是林分动态变化的关键。在今后的森林经营过程中可以通过合理的抚育间伐来调节林分的结构和土壤条件,进而促进森林生态系统碳汇能力的持续发挥。Carbon balance of the tree layer in natural forests is affected by three carbon pools:tree growth,mortality,and recruitment.However,the dynamics of the sink of each carbon pool and the driving factors are still unclear.To this end,we used stepwise regression method and structural equation model to assess the effects of biotic(stand and diversity)and abiotic(soil,topography and climate)factors on three dynamic processes of carbon sinks,namely,stand growth,recruitment and mortality,in the natural forests of Larix glemini,based on the data from the seventh and eighth national continuous forest inventory of the Greater Khingan Mountains.The results showed that the average growth,recruitment and mortality of L.glemini stand were 0.73,0.17 and 0.41 t·hm^(-2)·a^(-1).The growth of carbon sink in forest stands increased with the slope aspect index(the total path coefficientβ=0.135),stand basal area(β=0.132)and slope position(β=0.085),but decreased with the increases of average stand age(β=-0.225)and altitude(β=-0.196).Recruitment was negatively correlated with stand basal area(β=-0.368),average stand age(β=-0.240),soil pH(β=-0.184),soil total phosphorus(β=-0.115)and tree species richness(β=-0.012),and was positively correlated with soil total nitrogen(β=0.258).The larger important factors affecting mortality were the average tree height(β=0.276)>Simpson index(β=0.232)>soil total phosphorus(β=0.195)>stand basal area(β=0.154)>soil pH(β=0.084).Stand age,basal area and average tree height were the most important factors affecting stand carbon sink growth,recruitment and mortality.Topography and soil conditions were also the key to affect stand dynamics.Therefore,the structure and soil conditions of the forest can be adjusted through reasonable thinning in the management process,which in turn promotes the sustained fulfilment of forest carbon sink capacity.

关 键 词：生长量 进界量 枯损量 结构方程模型 林分断面积 林龄 林分平均树高 

分 类 号：S718.55[农业科学—林学]