温度是全球气候变化最重要的生态因子，过渡区生态系统的能量流动和物质循环过程极易受到气候变化的影响。为揭示暖温带-中温带过渡区森林土壤呼吸对温度变化的响应，选择在暖温带-中温带过渡区分布面积较大的长白落叶松（Larix olgensis）、红松（Pinus koraiensis）、油松（Pinus tabuliformis）人工林和天然阔叶混交林4种森林类型，利用Li-8100红外气体分析仪于2010─2013年连续观测土壤呼吸速率，同时利用森林小气候梯度观测系统连续同步观测大气温度、大气降水和土壤温度等环境因子，系统研究了土壤呼吸速率动态及其温度敏感性。结果表明：长白落叶松、红松、油松和阔叶混交林的年平均土壤呼吸速率（Rs，以CO2计）分别为（2.31±0.01）、（2.07±0.71）、（1.55±0.03）和（2.24±0.02）μmol·m2·s-1；4种森林类型的Rs与10 cm土壤温度（t10）均具有极显著的相关关系（P=0.000<0.01）；生长季期间落叶松、红松、油松人工林和天然阔叶混交林的Q10值分别为3.32、4.46、4.12和3.59，其中红松人工林Rs对t10的温度变化最敏感，而天然阔叶林和落叶松人工林的敏感性相对较低。本研究还对非生长季（11月─翌年3月）期间长白落叶松人工林的土壤呼吸进行了连续监测，并依据非生长季期间土壤温度的变化，将非生长季期间的土壤呼吸分为冻结期（t10-mean：10.0~2.0℃）、冻融期（t10-mean：0.5~2.0℃）和非冻结期（t10-mean：>2.0℃）3个阶段。结果显示：长白落叶松人工林在非生长季期间仍有微弱的呼吸作用（以CO2计，0.01~1.38μmol·m2·s-1），整个非生长季期间Rs与t10有极显著相关关系（r2=0.5863，P=0.000<0.01），非生长季冻结期的Rs与t10无显著相关关系（P=0.503>0.5），冻融期的Rs变化较剧烈，且较冻结期有较明显的增加；整个非生长季落叶松人工林的 Q10值为4.65，是生长季的1.40倍。研究结果对进一步阐明气候带过渡区不同森林类型土壤呼吸对气候变化的响应具有重要意义。%Soil carbon efflux in forests is a significant component in the terrestrial carbon cycle. Temperature is the major factor affecting forest soil respiration and very important in the context of global climate change in ecosystems in transition zones are vulnerable to the effects of climate change. Larch (Larix olgensis), Korean pine (Pinus koraiensis), Chinese pine (Pinus tabuliformis) plantations and natural broadleaved mixed forests, which are the major forest types in Northeast China, play important roles in forest ecosystem carbon cycles in China. In this study, a Li-8100 infrared gas analyzer was used to observe the soil respiration rate (Rs) from 2010 to 2013, and a forest gradient microclimate observation system was applied to continuously observe the air temperature, precipitation, soil temperature and other environmental factors. The relationship between Rs and soil temperature moisture in these four forests was analyzed over three years. The results showed that the mean Rs in Larch, Korean pine, and Chinese pine plantations and broadleaved mixed forest were (2.31±0.01), (2.07±0.71), (1.55±0.03) and (2.24±0.02)μmol·m-2·s-1, respectively. Moreover, Rs and soil temperature at a depth of 10 cm (t10) were significantly correlated (P=0.000<0.01). TheQ10 values in the four forests during the growing seasons were 3.32, 4.46, 4.12 and 3.59, respectively. The Rs of Korean pine plantation was more sensitive tot10 than the other three forests. Rs was also continuously monitored in a larch plantation during the non-growing season (from November to the following March), which revealed that the Rs in the non-growing season was divided into three stages: the frozen period (t10-mean:10.0~2.0℃), freeze-thaw period (t10-mean: 0.5~2.0℃) and thawing period (t10-mean: >2.0℃). A weak Rs was observed in larch plantations during the non-growing season (0.01~1.8μmol·m-2·s-1), and the Rs andt10values were significantly correlated throughout this period (r2=0.5863, P=0.000<0.01). Moreover, Rs andt10were not significantly correlated in the frozen period (P=0.503>0.05), Rs changes were more intense during the freeze-thaw period, and were significantly regulated variations when compared with the frozen period. Rs showed a greater increase during the freeze-thaw period than the frozen period. TheQ10 value of the larch plantation during the non-growing season was 4.65, which was 1.4 times that of the growing season. Overall, these findings suggest that Rs was more sensitive to global climate change during the non-growing season than the growing season for temperate forests.
展开▼
