采伐对温带小兴安岭岛状冻土区森林湿地碳源/汇的影响  

Impact of harvesting on carbon source/sink of forested wetlands at islandlike permafrost sites in temperate Xiaoxing’an mountains of China

作　　者：申忠奇 韩丽冬[1] 姜宁 郝丽[1] 牟长城[1] SHEN Zhongqi;HAN Lidong;JIANG Ning;HAO Li;MU Changcheng(Center for Ecological Research,Northeast Forestry University,Harbin 150040,Heilongjiang,China)

机构地区：[1]东北林业大学生态研究中心,黑龙江哈尔滨150040

出　　处：《中南林业科技大学学报》2020年第4期80-92,共13页Journal of Central South University of Forestry & Technology

基　　金：国家自然科学基金项目(31370461);国家重点研发计划项目(2016YFA0600803)。

摘　　要：【目的】北方泥炭地对气候变暖引起的冻土退化可能具有正负反馈作用,但其对采伐干扰引起的冻土退化如何响应却仍不清楚。【方法】采用静态箱-气象色谱法和相对生长方程法,同步测定温带小兴安岭岛状冻土区落叶松-泥炭藓沼泽不同采伐处理(D-对照、Z15-轻度择伐15%、Z45-强度择伐45%、J-皆伐)(采伐试验已10 a)样地的土壤呼吸年净碳排放量(CO2与CH4)、植被净初级生产力及年净固碳量及相关环境因子(温度、水位、化冻深度及土壤碳氮含量等),并依据生态系统净碳收支平衡,揭示采伐干扰对温带岛状冻土区森林湿地碳源/汇的中期影响规律及影响机制。【结果】1)择伐(Z15和Z45)使其土壤CH4年均通量(0.07~1.53 mg·m^-2h^-1)提高5.7~6.4倍(P>0.05),皆伐却使其显著提高20.9倍(P<0.05);2)采伐(择伐与皆伐)使其土壤CO2年均通量(84.94~106.35 mg·m^-2h^-1)降低14.5%~20.1%(P>0.05);3)采伐干扰改变了CH4排放的主控因子(由气温及5~10 cm土壤温度所控制转化为由气温、0~40cm土壤温度、水位、化冻深度及土壤碳氮比综合控制),但未改变CO2排放的主控因子(由温度、水位、化冻深度、土壤有机碳含量及碳氮比综合控制);4)其植被净初级生产力(3.94~7.18 t·hm^-2a^-1)和年净固碳量(1.79~4.46 tC·hm^-2a^-1)呈现出随采伐强度增大而递减趋势,皆伐和Z45使两者显著降低28.7%~45.1%和28.7%~59.9%(P<0.05),而Z15对其无显著影响(-1.8%和-2.7%,P>0.05);5)采伐干扰10 a后,择伐使其碳汇功能(-0.34~2.31 tC·hm^-2a^-1)初步得到恢复(Z15高于D 18.5%及Z45低于D 48.7%,P>0.05),而皆伐维持弱碳源(-0.34 tC·hm^-2a^-1,P<0.05)。【结论】在中国温带小兴安岭岛状冻土区森林湿地碳汇管理实践中宜采取中、低强度的择伐方式,而应避免对其进行皆伐。【Objective】Northern peatlands may have positive and negative feedback on permafrost degradation caused by climate warming,yet how it responds to that caused by logging disturbances remains unclear.【Method】The fluxes of CO2 and CH4 emissions,net primary productivity(NPP)and annual net carbon sequestration(ANCS)from Larix gmelinii-marsh forested wetlands under different cutting treatments(Control-D,light selective cutting(15%)-Z15,strength cutting(45%)-Z45 and clear cutting-J)(the harvesting test has been done for 10 years)were measured synchronously by using the static chamber gas chromatography method and the relative growth equation,as well as related environmental factors(such as temperature,water level,freezing depth and soil carbon and nitrogen content,etc.)at temperate island-like permafrost habitats in Xiaoxing’an mountains of China,so as to reveal the medium-term effects of harvesting disturbance on carbon source/sink of temperate forested wetlands at island-like permafrost sites according to net carbon budget of ecosystem.【Result】1)Selective cutting(Z15 and Z45)increased the mean annual flues of CH4emissions by 5.7-6.4 times(P>0.05),but the clear cutting made it significantly increased by 20.9 times(P<0.05),compared to the control;2)Harvesting(selective cutting and clear cutting)reduced the mean annual fluxes of CO2 emissions by 14.5%-20.1%(P>0.05);3)Harvesting disturbance changed the main control factor of CH4 emission(converted from temperature and 5—10cm soil layer temperature to temperature,0—40cm soil layer temperature,water level,freezing depth and soil carbon to nitrogen ratio),but those of CO2 emissions were not changed(which generally controlled by temperature,water level,freezing depth,soil organic carbon content and carbon to nitrogen ratio);4)Both NPP(3.94-7.18 t·hm^-2·a^-1)and ANCS(1.79-4.46 tC·hm^-2·a^-1)showed a decreasing trend with increasing harvesting intensity,and clear cutting and Z45 made NPP and ANCS significantly decreased by 28.7%-45.1%and 28.7%-59.9%(P<0.05)

关 键 词：温带小兴安岭 岛状冻土区 森林沼泽湿地 碳源/汇 采伐影响 

分 类 号：S718·556[农业科学—林学]