Meeting the reporting requirements of the Kyoto Protocol has focused attention on the potential of forests in sustainably sequestering carbon (C) to mitigate the effects of rising levels of atmospheric CO₂. Much uncertainty remains concerning the ultimate effect of management on such sequestration effects. The management of woody debris (WD) and other deadwood stocks is an example of a management intervention with the scope of affecting the source-sink dynamics of forest C. Windrowing is the most commonly employed approach to the management of post-harvest WD. This study investigated the quantities of windrowed deadwood C across a chronosequence of reforested commercial Sitka spruce stands in Ireland and how its decomposition rate affected its contribution to forest C sequestration. The C stocks in windrowed WD ranged from 25 to 8 t C ha⁻¹ at the 4- and 16-year-old stands, respectively. Losses due to the decomposition of these stocks ranged from 5.15 t C ha⁻¹ yr⁻¹ at the youngest site (4 years old) to 0.68 t C ha⁻¹ yr⁻¹ at the oldest site (16 years old). Using a visual decay-class categorization of WD components and an assessment of wood density, decay rate constants were estimated for logs, branches, and stumps (the main WD constituents of windrows) as 0.037, 0.038, and 0.044, respectively. These results, derived from stand stock evaluations, were placed into context with data previously published from the same chronosequence that characterized the day-to-day fluxes to or from this pool. This comparison indicated that though only a very small quantity of C was lost in dissolved leachate form, the most significant pathway for loss was respiratory and ranged from 16 to 8 t C ha⁻¹ yr⁻¹ at the 9- and 16-year-old sites. These estimates were many times greater in extent than estimates made using a density-loss approach, the difference indicating that fragmentation and weathering play a large role in woody decomposition in intensively managed forests.

中文翻译：

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在长达16年的时间序列分解腐烂的Sitka云杉木本碎片产生的碳损失

满足《京都议定书》的报告要求，将注意力集中在森林在可持续固存碳（C）以减轻大气CO ₂含量升高的影响方面的潜力。关于管理对这种螯合效应的最终效果，仍然存在许多不确定性。木屑（WD）和其他阔叶木资源的管理是一种管理干预措施的例子，其范围会影响森林C的源汇动态。割草是最常用的收获后WD管理方法。这项研究调查了爱尔兰经过重新造林的锡特卡云杉林分按时间顺序排列的随行杂木C的数量，及其分解速率如何影响其对森林C固存的贡献。在4年和16年生的展位上，WD堆肥的C储量分别为25至8 t C ha ^-1。这些储备的分解所造成的损失为5.15 t C ha ^-1 yr ^-1最年轻的站点（16岁）处的最年轻站点（4岁）至0.68 t C ha ^-1 yr ^-1。使用WD组件的可视衰减类分类并评估木材密度，原木，树枝和树桩（秸秆的主要WD组件）的衰减速率常数估计分别为0.037、0.038和0.044。这些来自标准储备评估的结果与先前从同一时间序列发布的数据进行了关联，这些时间序列表征了该库的日常通量。该比较表明，尽管只有极少量的C以溶解的渗滤液形式损失，但最主要的损失途径是呼吸，范围为16至8 t C ha ^-1 yr ^-1在9岁和16岁的网站上。这些估计值的范围比使用密度损失法得出的估计值大很多倍，差异表明，碎片化和风化在集约化经营森林的木质分解中起很大作用。