中国东北地区阔叶红松林与兴安落叶松林的碳通量特征及其影响因子比较

Comparisons of carbon flux and its controls between broad-leaved Korean pine forest and Dahurian larch forest in northeast China

北半球中高纬度的森林生态系统在全球碳循环过程中扮演着非常重要的角色。基于中国东北地区阔叶红松林与兴安落叶松林2007年和2008年2a生长季的涡度相关通量资料及气象观测资料,比较分析了两类生态系统的碳通量特征及其环境控制因子。结果表明:研究期间,阔叶红松林与兴安落叶松林都表现为碳吸收,强度分别为199gCm-2(阔叶红松林2a生长季平均值)与49gCm-2(兴安落叶松林2008年生长季);阔叶红松林碳吸收强度在生长季的大部分时段都大于兴安落叶松林。半小时尺度上,两类生态系统的呼吸作用均与10cm土壤温度呈显著的指数相关,兴安落叶松林生态系统呼吸的温度敏感性(Q10=3.44)显著大于阔叶红松林(Q10=1.90);日尺度上,阔叶红松林与兴安落叶松林碳释放/吸收的转变临界温度为10℃左右。研究期间,兴安落叶松林生态系统的水分利用效率高于阔叶红松林生态系统。

Forest ecosystem in northern middle and high latitudes play an important role in global carbon cycle.Based on eddy covariance flux data and meteorological observations in the growing seasons of 2007 and 2008,the characteristics of CO2 flux and its controls were compared between broad-leaved Korean pine forest and Dahurian larch forest in northeast China.The results showed that both forest ecosystems acted as net sinks of CO2 during the study period,with a magnitude of 199 g C m-2（ the average of 2007 and 2008 for broad-leaved Korean pine forest） and 49 g C m-2（ the value of 2008 for Dahurian larch forest） respectively.The broad-leaved Korean pine forest ecosystem sequestered more carbon than the Dahurian larch forest ecosystem in most days of the growing season.Respirations of these two ecosystems showed exponential correlations well with the 10 cm soil temperatures on half-hour scale,and the temperature sensitivity index （ Q10 ） of respiration in the Dahurian larch forest ecosystem （ 3.44） was much larger than in the broad-leaved Korean pine forest ecosystem （ 1.90） .The critical transition temperature from carbon release to carbon uptake on daily scale was around 10 ℃ for these two ecosystems.Water-use efficiency was higher in the Dahurian larch forest ecosystem than in the broad-leaved Korean pine forest ecosystem.