Ecosystem respiration and its components in an old-growth forest in the Great Lakes region of the United States
Ecosystem respiration and its components in an old-growth forest in the Great Lakes region of the United States
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DOI：
10.1016/j.agrformet.2007.08.008
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发表时间：
2008-02
影响因子：
6.2
通讯作者：
Jianwu Tang;P. Bolstad;A. Desai;Jonathan G Martin;B. Cook;K. Davis;Eileen V. Carey
中科院分区：
文献类型：
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作者：
Jianwu Tang;P. Bolstad;A. Desai;Jonathan G Martin;B. Cook;K. Davis;Eileen V. Carey
生态系统呼吸及其组分对年龄、物种、林分结构和环境条件非常敏感，对生态系统净生产力有重要影响。2002年和2003年在美国密歇根州北部以硬木和铁杉为主的原始林分测量了生态系统呼吸和组分呼吸，包括土壤、木屑、茎和叶呼吸。呼吸主要受温度控制，7 - 8月为高峰，1 - 3月为最低。硬木林分生态系统呼吸总量平均为1013gCm−2y−1，铁杉林分生态系统呼吸总量平均为922gCm−2y−1。硬木林分年累积土壤呼吸、粗木屑呼吸、茎呼吸和叶呼吸分别为724、43、131、115gCm−2y−1，占总生态系统呼吸的72%、4%、13%和11%；铁杉林分年累积土壤呼吸、粗木屑呼吸、茎呼吸和叶呼吸分别为614、29、207、72gCm−2y−1，占总生态系统呼吸的67%、3%、22%和8%。除叶片呼吸外，2002年生态系统呼吸及其各组分均大于2003年，主要原因是2003年气温较低。硬木林分除茎部呼吸外的其他组分呼吸均高于铁杉林分。日平均生态系统呼吸由室内测量值升级后与涡动相关方差测量值吻合较好，r2为0.96。在室内测量的基础上，通过比较老林与附近幼林和成熟次生林的呼吸作用，我们发现年龄和树种对决定组分呼吸作用的大小和比例都很重要。总的生态系统呼吸从幼林到成熟林依次增加，从成熟林到原生林依次减少。
Ecosystem respiration and its components are sensitive to age, species, stand structure, and environmental conditions, and substantially influence net ecosystem productivity. We measured ecosystem respiration and component respiration including soil, woody debris, stem and leaf respiration in old-growth hardwood-dominated and hemlock-dominated stands in northern Michigan, USA in 2002 and 2003. Respiration was mainly controlled by temperature, peaked in July–August and reached minimums in January–March. Total ecosystem respiration averaged 1013gCm−2y−1in the hardwood stand and 922gCm−2y−1in the hemlock stand. Cumulative annual soil respiration, coarse woody debris respiration, stem respiration, and leaf respiration were 724, 43, 131, 115gCm−2y−1, respectively, accounting for 72%, 4%, 13%, and 11% of total ecosystem respiration in the hardwood stand, and 614, 29, 207, 72gCm−2y−1, respectively, accounting for 67%, 3%, 22%, and 8% in the hemlock stand. Ecosystem respiration and its components except for leaf respiration in 2002 were larger than year 2003 due primarily to lower temperature in 2003. Component respiration except for stem respiration was higher in the hardwood stand than the hemlock stand. Daily mean ecosystem respiration upscaled from chamber measurements agreed well with eddy covariance measurements, with r2of 0.96. By comparing respiration from the old-growth with a nearby young and a mature second-growth forest based on chamber measurements, we found that both age class and species are important in determining the magnitude and proportion of component respiration. Total ecosystem respiration generally increased from the young forest to the mature forest, and then decreased from the mature to the old-growth forest.