Individual- and stand-level stem CO 2 efflux in a subtropical Schima superba plantation
Individual- and stand-level stem CO 2 efflux in a subtropical Schima superba plantation
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DOI：
10.5194/bg-9-3729-2012
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发表时间：
2012-10
期刊：
影响因子：
4.9
通讯作者：
Liwei Zhu;P. Zhao;G. Ni;Q. Cao;C. M. Zhou;Xiaomin Zeng
中科院分区：
文献类型：
--
作者：
Liwei Zhu;P. Zhao;G. Ni;Q. Cao;C. M. Zhou;Xiaomin Zeng
抽象的。树干呼吸是森林生态系统总呼吸的一个重要组成部分，但研究较少。2010年8月和12月，采用开放式气体交换系统，对华南地区木荷人工种植园的林分微气候和树干温度进行了连续监测，并对树干CO2排放进行了研究。研究了不同季节呼吸的温度响应、树干CO2排放量沿树干沿着的垂直变化以及林分水平的CO2排放量。树干体积被认为是树干CO2排放量的较好的相关因子，并被用作本研究中林分水平树干CO2排放量估计的标量。木荷种植园基于体积的茎CO2排放量在2 m处高于1.3 m处。8月和12月的平均树干CO2排放量分别为268.9和104.6 μmol m−3 s−1，表明树干CO2排放量存在显著的季节变化。在我们的研究期间，茎CO2流出的温度响应保持恒定，Q10值为1.9和1.8。在这个亚热带的S。木荷种植园在8月和12月1.3m高度处的CO2排放量平均值分别为3.36和1.26 μmol m−2 s−1。研究结果表明，树干CO2排放具有恒温响应，树干CO2排放的季节变化主要受树干温度的控制，在林分水平估算中应考虑树干CO2排放的垂直变化。
Abstract. Stem respiration is an important, but poorly studied component of total forest ecosystem respiration. Stem CO2 efflux was investigated with an open gas exchange system while stand microclimate and stem temperature were continuously monitored in a Schima superba plantation in South China for several days in August and December 2010. The temperature response of respiration in the different seasons, the vertical variation in stem CO2 efflux along the stem, and the stand-level stem CO2 efflux were examined. Stem volume was identified as the better correlate for stem CO2 efflux and was used as the scalar for the stand-level estimates of stem CO2 efflux in this S. superba plantation. Volume-based stem CO2 efflux was higher at 2 m than at 1.3 m. Mean stem CO2 efflux was 268.9 and 104.6 μmol m−3 s−1 in August and December, respectively, indicating a dramatic seasonal variation of stem CO2 efflux. The temperature response of stem CO2 efflux remained constant during our study period with Q10 values of 1.9 and 1.8. In this subtropical S. superba plantation, stem CO2 efflux per unit ground area averaged 3.36 and 1.26 μmol m−2 s−1 based on the measurement data at 1.3-m height of the stem in August and December, respectively. Our results suggest that stem CO2 efflux has a constant temperature response, and the seasonal variation in stem CO2 efflux is mainly controlled by stem temperature, and the vertical variation in stem CO2 efflux needs to be considered in the stand-level estimation.