As a key component of the Earth system, roots play a key role in linking Earth's lithosphere, hydrosphere, biosphere and atmosphere. Here we combine 10 307 field measurements of forest root biomass worldwide with global observations of forest structure, climatic conditions, topography, land management and soil characteristics to derive a spatially explicit global high-resolution (∼ 1 km) root biomass dataset, including fine and coarse roots. In total, 142 ± 25 (95 % CI) Pg of live dry-matter biomass is stored belowground, representing a global average root : shoot biomass ratio of 0.25 ± 0.10. Earlier studies (Jackson et al., 1997; Robinson, 2007; Saugier et al., 2001) are 44 %–226 % larger than our estimations of the total root biomass in tropical, temperate and boreal forests. The total global forest root biomass from a recent estimate (Spawn et al., 2020) is 24 % larger than this study. The smaller estimation from this study is attributable to the updated forest area, spatially explicit aboveground biomass density used to predict the patterns of root biomass, new root measurements and the upscaling methodology. We show specifically that the root shoot allometry is one underlying driver that has led to methodological overestimation of root biomass in previous estimations. Raw datasets and global maps generated in this study are deposited at the open-access repository Figshare (https://doi.org/10.6084/m9.figshare.12199637.v1; Huang et al., 2020).

中文翻译：

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世界森林根系生物量的全球地图

作为地球系统的重要组成部分，根系在连接地球的岩石圈、水圈、生物圈和大气层方面发挥着关键作用。在这里，我们将全球森林根生物量的 10 307 场实地测量与森林结构、气候条件、地形、土地管理和土壤特征的全球观测相结合，以推导出空间明确的全球高分辨率（~  1 公里）根生物量数据集，包括精细和粗根。总共有 142  ±  25 (95 % CI) Pg 的活干物质生物量储存在地下，代表全球平均根系：地上部生物量比为 0.25  ± 0.10。早期的研究（Jackson 等人，1997 年；Robinson，2007 年；Saugier 等人，2001 年）比我们对热带、温带和北方森林中总根生物量的估计大 44%–226%。根据最近的估计（Spawn 等人，2020 年），全球森林根系总生物量比本研究大 24%。本研究的较小估计值归因于更新的森林面积、用于预测根生物量模式的空间明确的地上生物量密度、新根测量和升级方法。我们特别表明，根茎异速生长是导致先前估计中对根生物量方法论高估的潜在驱动因素。本研究中生成的原始数据集和全球地图存放在开放存取存储库 Figshare (https://doi.org/10.6084/m9.figshare.12199637.v1;