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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >ANNUAL CARBON COST OF AUTOTROPHIC RESPIRATION IN BOREAL FOREST ECOSYSTEMS IN RELATION TO SPECIES AND CLIMATE
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ANNUAL CARBON COST OF AUTOTROPHIC RESPIRATION IN BOREAL FOREST ECOSYSTEMS IN RELATION TO SPECIES AND CLIMATE

机译：与物种和气候有关的针叶林生态系统自养呼吸的年度碳成本

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Autotrophic respiration (R-a) in forest ecosystems can be >50% of the carbon fixed in photosynthesis and may regulate productivity and carbon storage in forest ecosystems, because R-a increases with temperature. We estimated annual R-a from chamber measurements in aspen, black spruce, and jack pine forests in Canada for 1994. Mean foliage respiration at 10 degrees C for expanded leaves was 0.21-0.95 mu mol m(-2) (leaf surface) s(-1) for all species and differed little from May to September. Wood respiration at 15 degrees C (0.2-1 mu mol m(-2) (stem surface) s(-1) for all species) was strongly seasonal, with high rates in midsummer that coincided with wood growth. Fine root respiration at 10 degrees C was 2.5-7.7 mu mol kg(-1) s(-1) for all species and declined throughout the growing season for the conifers. Annual costs of R-a for foliage, wood, and roots (overstory and understory) were 490, 610, and 450 g C m(-2) (ground) yr(-1) for aspen, black spruce, and jack pine (old) in northern Manitoba and 600, 480, and 310 g C m(-2) yr(-1) for aspen, black spruce, and jack pine (old) in central Saskatchewan. Carbon use efficiency (CUE), the ratio of net production to production plus R-a, averaged 0.34, 0.34, and 0.39 for aspen, black spruce, and jack pine (old) for all tissues and 0.61, 0.36, and 0.44 for aboveground tissues. Differences in CUE between the northern and the southern sites were small for all species, and CUE did not vary with stand biomass. Species differences in CUE suggest that models assuming a constant CUE across species may poorly estimate production and carbon balance for any given site. [References: 49]
机译：森林生态系统中的自养呼吸（R-a）可能超过光合作用中固定碳的50％，并可能调节森林生态系统中的生产力和碳存储，因为R-a随着温度的升高而增加。我们通过1994年加拿大白杨，黑云杉和杰克松林的室内测量值估算了年度Ra。在10摄氏度下，膨胀叶的平均叶呼吸为0.21-0.95μmol m（-2）（叶表面）s（- 1）对于所有物种，从五月到九月差异很小。在15摄氏度（所有物种的0.2-1μmol m（-2）（茎表面）s（-1））下，木材呼吸呈强烈的季节性变化，盛夏时分的呼吸速率与木材的生长同步。对于所有物种，在10摄氏度下的细根呼吸作用为2.5-7.7μmol kg（-1）s（-1），在整个针叶树的整个生长季节中均下降。树叶，木材和根部（上层和下层）的Ra年度成本分别为白杨木，黑云杉和杰克松（旧）的490、610和450 g C m（-2）（地面）yr（-1）。在马尼托巴北部，以及在萨斯喀彻温省中部的白杨木，黑云杉和千斤顶松木（旧）的600、480和310 g C m（-2）yr（-1）。碳使用效率（CUE），净产量与产量加上R-a的比率对所有组织平均为白杨木，黑云杉和杰克松（老）为0.34、0.34和0.39，对于地上组织平均为0.61、0.36和0.44。对于所有物种而言，北部和南部站点之间的CUE差异均很小，并且CUE不会随林分生物量而变化。 CUE的物种差异表明，假设物种间CUE恒定的模型可能无法很好地估计任何给定地点的生产和碳平衡。 [参考：49]

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