Toward inventory-based estimates of soil organic carbon in forests of the United States
Toward inventory-based estimates of soil organic carbon in forests of the United States
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DOI：
10.1002/eap.1516
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发表时间：
2017-06-01
影响因子：
5
通讯作者：
Swanston, C. W.
中科院分区：
文献类型：
--
作者：
Domke, G. M.;Perry, C. H.;Swanston, C. W.
土壤有机碳（SOC）是地球上最大的陆地碳（C）汇，在生态系统过程和气候变化中起着重要作用。考虑到测量SOC所需的成本和时间，特别是SOC的变化，许多联合国气候变化框架公约的签署国报告使用政府间气候变化专门委员会或国家特定模型的默认值来估计SOC储量和储量变化。在美国，森林中的SOC由美国农业部林务局的森林清查和分析（FIA）计划进行的国家森林清查（NFI）进行监测。自2001年以来，FIA计划一直在测量土壤属性，作为NFI的一部分，并积累了大量的SOC库存林地在美国接壤的东南部和中南部沿海阿拉斯加。也就是说，FIA计划一直在使用特定国家的SOC预测，部分基于使用自然资源保护局编制的国家土壤地理（STATSGO）数据库中SOC估计值的模型。从STATSGO数据库获得的估计值是大地图单元的平均值，预计不会提供特定位置的准确估计值，例如，NFI图。为了提高美国森林中SOC估计的准确性，NFI SOC观测首次用于预测所有森林NFI样地100 cm深度的SOC密度。将土壤形成因素沿着与SOC的观测结果结合到一个新的估计框架中，导致全国SOC密度增加了75%（48 +/- 0.78 Mg/ha）。这大大增加了SOC库的贡献，从约44%（17 Pg）的总森林生态系统C库存的56%（28 Pg），在美国的森林C预算。
Soil organic carbon (SOC) is the largest terrestrial carbon (C) sink on Earth; this pool plays a critical role in ecosystem processes and climate change. Given the cost and time required to measure SOC, and particularly changes in SOC, many signatory nations to the United Nations Framework Convention on Climate Change report estimates of SOC stocks and stock changes using default values from the Intergovernmental Panel on Climate Change or country-specific models. In the United States, SOC in forests is monitored by the national forest inventory (NFI) conducted by the Forest Inventory and Analysis (FIA) program within the U.S. Department of Agriculture, Forest Service. The FIA program has been consistently measuring soil attributes as part of the NFI since 2001 and has amassed an extensive inventory of SOC in forest land in the conterminous United States and southeast and southcentral coastal Alaska. That said, the FIA program has been using country-specific predictions of SOC based, in part, upon a model using SOC estimates from the State Soil Geographic (STATSGO) database compiled by the Natural Resources Conservation Service. Estimates obtained from the STATSGO database are averages over large map units and are not expected to provide accurate estimates for specific locations, e.g., NFI plots. To improve the accuracy of SOC estimates in U.S. forests, NFI SOC observations were used for the first time to predict SOC density to a depth of 100 cm for all forested NFI plots. Incorporating soil-forming factors along with observations of SOC into a new estimation framework resulted in a 75% (48 +/- 0.78 Mg/ha) increase in SOC densities nationally. This substantially increases the contribution of the SOC pool, from approximately 44% (17 Pg) of the total forest ecosystem C stocks to 56% (28 Pg), in the forest C budget of the United States.