长白山阔叶红松林碳收支特征

植被-大气间CO2交换研究对准确评价陆地生态系统碳收支有重要意义．该研究采用开路式涡动相关系统对长白山阔叶红松林的C O2交换特征进行了整年连续监测．结果表明，该森林生态系统的碳交换季节变化明显，2003年森林净生态系统碳交换量(NEE)变化范围在-6.37～2.13 g/(m2·d)之间，5—9月均表现为碳汇，其余月份为碳源，其中净碳吸收量与释放量最大的月份分别为6和10月；全年森林净吸收的碳量为-191.3 g/m2，整体表现为一定强度的碳汇．影响NEE的环境因子主要是光合有效辐射(PAR)和土壤温度等，白天NEE对PAR 的响应符合直角双曲线方程，夜间的NEE与5 cm深土壤温度有较好的指数关系．生态系统呼吸释放对温度响应的敏感性(Ｑ10)为3.17． 

Carbon budget characteristics of the broadleaved Korean pine forests in Changbaishan Mountains

Studies on CO2 exchange between vegetation and atmosphere can enhance the scientific understanding and modelling of carbon budget on terrestrial ecosystem. As a part of the ChinaFLUX program, CO2 flux was measured for year_round in 2003 by an open_path eddy covariance system over a broadleaved Korean pine forests in northeastern China. The net ecosystem carbon exchange (NEE) between forest and atmosphere ranged from -6.37 to 2.13 g/(m2·d) during the observational year, with the net carbon assimilation peak occurred in June, and a highest net carbon efflux occurred in October. The nocturnal NEE showed an exponential regression relationship with 5 cm depth soil temperature, and the CO2 respiration Q10 of ecosystem was 3.17. With the increase of photosyntheticactive radiation(PAR), CO2 flux changes were in well accordance with the curve of Michaelis Menten model. The total NEE was -191.3 g/m2 in 2003, which indicated that the broadleaved Korean pine forests of Changbaishan Mountains were functioning as a moderate carbon sink.