Department of Biological Sciences, School of Natural Sciences, University of Limerick, Limerick, Ireland.
UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland.
Glob Chang Biol. 2021 Aug;27(15):3681-3698. doi: 10.1111/gcb.15654. Epub 2021 May 27.
Drainage and conversion of natural peatlands to forestry increases soil CO emissions through decomposition of peat and modifies the quantity and quality of litter inputs and therefore the soil carbon balance. In organic soils, CO net emissions and removals are reported using carbon emission factors (EF). The choice of specific default Tier 1 EF values from the IPCC 2013 Wetlands supplement depends on land-use categories and climate zones. However, Tier 1 EF for afforested peatlands in the temperate maritime climate zone are based on data from eight sites, mainly located in the hemiboreal zone, and the uncertainty associated with these default values is a concern. In addition, moving from Tier 1 to higher-Tier carbon reporting values is highly desirable when large areas are affected by land-use changes. In this study, we estimated site-specific soil carbon balance for the development of Tier 2 soil CO -C EFs for afforested peatlands. Soil heterotrophic respiration and aboveground tree litterfall were measured during two years at eight afforested peatland sites in Ireland. In addition, fine-root turnover rate and site-specific fine-root biomass were used to quantify belowground litter inputs. We found that drainage of peatlands and planting them with either Sitka spruce or lodgepole pine, resulted in soils being net carbon sources. The soil carbon balance at multi-year sites varied between 63 ± 92 and 309 ± 67 g C m year . Mean CO -C EF for afforested peatlands was 1.68 ± 0.33 t CO -C ha year . The improved CO -C EFs presented here for afforested peatlands are proposed as a basis to update national CO -C emissions from this land-use class in Ireland. Furthermore, new data from these sites will significantly contribute to the development of more reliable IPCC default Tier 1 CO -C EFs for afforested peatlands in the maritime temperate climate zone.
排水和将天然泥炭地转换为林业会增加土壤 CO 的排放，这是由于泥炭分解以及改变了凋落物输入的数量和质量，从而改变了土壤碳平衡。在有机土壤中，使用碳排放因子（EF）报告 CO 净排放量和清除量。选择源自 IPCC 2013 年湿地补充附录的特定默认 Tier 1 EF 值取决于土地利用类别和气候带。然而，温带海洋性气候带造林后的泥炭地的 Tier 1 EF 值是基于来自八个地点的数据，这些地点主要位于北温带，这些默认值的不确定性令人担忧。此外，当大面积受到土地利用变化的影响时，从 Tier 1 转移到更高的 Tier 碳报告值是非常可取的。在这项研究中，我们针对造林后的泥炭地开发了特定于站点的 Tier 2 土壤 CO-C EF 值，对其土壤碳平衡进行了估算。在爱尔兰的八个造林后的泥炭地站点，我们进行了为期两年的土壤异养呼吸和地上树木凋落物的测量。此外，还使用细根周转率和特定于站点的细根生物量来量化地下凋落物的输入。我们发现，泥炭地的排水和种植欧洲云杉或火炬松会导致土壤成为净碳源。多年站点的土壤碳平衡在 63 ± 92 和 309 ± 67 g C m-1 年之间变化。造林后的泥炭地的平均 CO-C EF 值为 1.68 ± 0.33 t CO-C ha-1 年。本文提出的造林后的泥炭地的改进后的 CO-C EF 值，拟作为爱尔兰更新这一土地利用类别下 CO-C 排放量的基础。此外，这些站点的新数据将为开发更可靠的 IPCC 温带海洋性气候带造林后的泥炭地默认 Tier 1 CO-C EF 值做出重要贡献。
