论文部分内容阅读
物种丰富的异龄老龄森林对陆地生态系统动态模型及全球碳收支具有十分重要的意义.目前,我国关于老龄森林碳通量的研究很少,亚热带地区的老龄林更鲜有报道.本研究利用涡度相关技术观测了我国中亚热带地区的浙江天目山一个老龄常绿落叶阔叶混交林生态系统的CO_2通量.以2013年7月到2014年6月的观测数据为依据,分析了此老龄林净生态系统碳交换量(NEE)、生态系统呼吸量(R_e)、生态系统总交换量(GEE)的变化.结果表明:研究期间老龄林常绿落叶阔叶混交林生态系统NEE月总量除12、2月为正值外(表现为碳源),其余月份均为负值(表现为碳汇).NEE月总量平均为-61.52 g C·m~(-2),各月碳吸收量以6月(-149.40 g C·m~(-2))最高,10月次之,呈双峰变化;最大碳源出现在2月(23.45g C·m~(-2)).各月NEE平均日变化差异明显,6月的平均通量峰值最大,达到-0.98 mg·m~(-2)·s~(-1),12月最小,为-0.35mg·m~(-2)·s~(-1);NEE符号改变的时间也呈明显的季节变化特征;全年NEE、R_e、GEE分别为-738.18、931.05、-1669.23g C·m~(-2).与相近纬度相近林型的其他森林生态系统相比,由于其复层结构和多种幼龄更新树木的存在,其测定的固碳量较大.表明我国中亚热带天目山地区的老龄森林生态系统不是处于碳收支稳定状态,而是具有相对较高的固碳能力.
Species-rich Aging Aged Forests are of great significance to dynamic models of terrestrial ecosystems and global carbon budget.At present, there are few studies on the carbon fluxes of old forests in China, and there are few reports on the aged forests in subtropical regions.In this study The CO_2 flux in an aged evergreen and deciduous broad-leaved mixed forest ecosystem in Tianmu Mountain of Zhejiang Province in the subtropical region of China was measured by using the eddy covariance technique.According to the observation data from July 2013 to June 2014, (NEE), ecosystem respiration (R_e) and total ecosystem exchange (GEE) of forest net ecosystem.The results showed that the total monthly NEE of the evergreen and deciduous broad-leaved mixed forest ecosystem Except for positive values in 12 and February, which showed carbon sources, all the other months were negative (represented by carbon sinks). The total monthly NEE was -61.52 g C m -2, The amount of uptake was highest in June (-149.40 g C m -2), followed by a bimodal change in October, and the maximum carbon source appeared in February (23.45 g C m -2). The average daily diurnal variation of NEE in each month was significantly different. The average peak flux of June was the highest, reaching -0.98 mg · m -2 · s -1, the lowest in December was -0.35 mg · m -1, 2 ) · S ~ (-1). The time of changing NEE sign also showed obvious seasonal variation. The annual NEE, R_e and GEE were -738.18,931.05 and -1669.23g C · m -2, respectively Compared with other forest ecosystems with similar latitudes, the measured carbon sequestration was larger because of its multi-layered structure and many young trees, which indicated that the aged forest ecosystem in the Tianmu Mountain area in China is not in the carbon Revenue and expenditure steady state, but with a relatively high carbon sequestration capacity.