Leaf litter decomposition strongly affects the global carbon cycle through carbon dioxide (CO 2) emissions to the atmosphere. The litter bag method (LB) and chamber method with litter addition and removal treatments (C-LART) have been used to quantify the litter decomposition rate and its resultant CO2 flux. The C-LART method measures soil CO2 fluxes in control, litter addition, and litter removal plots, and thereby decomposition rates are calculated from differences of the fluxes. However, no report has described the applicability of C-LART in comparison with LB. This study measured the litter decomposition rate and its resultant CO2 flux using C-LART and LB in a temperate evergreen forest in central Japan to assess the applicability of the two methods. Annual soil respiration in the control plot was 1572 gC m yr, which was approximately twice as high as the mean of temperate evergreen forests in the world. The litter decomposition rate was 0.42 g g yr in mass loss or 0.49 gC gC yr in carbon loss by LB, which are compatible with those reported from other temperature forests. In contrast, the decomposition rate of litter carbon ascertained using C-LART was greater than 1 (1.96-3.76 gC gC yr), meaning that carbon emissions increased more than applied, and that the carbon emissions were decreased more than those removed by litter treatments. The incredibly high decomposition was attributed to the enhanced or restricted microbial activities in the underlying mineral soil. Changes in microbial activity are probably caused by the alteration of material supply from the leaf litter layer to the soil by litter treatment (the priming effect). In conclusion, C-LART is not applicable to evaluate CO2 emissions through litter decomposition. Another approach must be used to compensate the priming effect for application of the chamber method.

中文翻译：

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测量温带森林落叶分解产生的CO ₂排放的垃圾袋法和室内法的比较

落叶分解通过向大气排放二氧化碳 (CO 2) 强烈影响全球碳循环。垃圾袋法 (LB) 和带有垃圾添加和清除处理的室法 (C-LART) 已被用于量化垃圾分解率及其产生的 CO2 通量。C-LART 方法测量控制、凋落物添加和凋落物清除地块中的土壤 CO2 通量，从而根据通量的差异计算分解率。然而，没有报告描述 C-LART 与 LB 相比的适用性。本研究使用 C-LART 和 LB 在日本中部的温带常绿林中测量凋落物分解率及其产生的 CO2 通量，以评估这两种方法的适用性。对照样地的年土壤呼吸为 1572 gC m yr，大约是世界温带常绿林平均值的两倍。LB 的凋落物分解率为 0.42 gg yr 的质量损失或 0.49 gC gC yr 的碳损失，这与其他温度森林报告的结果一致。相比之下，使用 C-LART 确定的凋落物碳的分解率大于 1 (1.96-3.76 gC gC yr)，这意味着碳排放量的增加大于应用量，并且碳排放量减少的量大于通过凋落物处理去除的碳排放量. 令人难以置信的高分解归因于底层矿质土壤中微生物活动的增强或限制。微生物活性的变化可能是由于凋落物处理（引发效应）改变了从凋落物层到土壤的物质供应。综上所述，C-LART 不适用于通过垃圾分解评估 CO2 排放。必须使用另一种方法来补偿腔室方法应用的启动效应。