Key message

Tree roots hold soil that is dramatically heavier than the tree biomass, wet or dried. This soil might compensate for the imbalance between above- and belowground mass.

Abstract

Root–soil plates are recognized to play an important role in root anchorage of plate-like root system, however, actual measurements of their mass have rarely been reported. Even though the root–soil plate mass is often estimated using aboveground allometric indices, no research confirms the validity. Seven root–soil plates of Cryptomeria japonica fallen by Typhoon Jebi were divided into roots and soil, and their weights were directly measured. Mass of the seven plates ranged from 251 to 3070 kg on a dry basis. Roots accounted for 8% of total plate mass and soil for 92%. The mass of the soil held in the plates was 2.8 times greater than tree biomass. The root-to-shoot biomass ratio was 0.26, whereas the ratio of root–soil plate mass to shoot biomass was 3.9, meaning that the root–soil plate mass was much greater than aboveground biomass. These results suggest that the soil mass held in the plate is the main component of whole-tree mass including the plate. The root system holds soil weighing as much as 13 times the root system’s mass. The soil might balance the aboveground weight of the tree by adding mass. Aboveground allometric indices are good indicators of root–soil plate mass and allow the belowground mass to be estimated to understand tree anchorage without soil disturbance.

中文翻译：

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树木根系土壤质量的定量评估

关键信息

树木的根部土壤比潮湿或干燥的树木生物量重得多。这种土壤可以弥补地上和地下质量之间的不平衡。

抽象

根-土板在板状根系的根系锚固中起着重要作用，然而，很少有关于其质量的实际测量报告。即使经常使用地上倾角指数估算根-土板质量，也没有研究证实其有效性。七个柳杉根土壤板台风杰比（Jebi）摔倒后，将其分为根部和土壤，并直接测量其重量。以干基计，这七个板的质量范围为251至3070kg。根系占板块总质量的8％，土壤占92％。板中的土壤质量是树木生物量的2.8倍。根茎生物量比为0.26，而根-土壤板块质量与芽生物量的比率为3.9，这意味着根-土壤板块质量比地上生物量大得多。这些结果表明，板块中保持的土壤质量是包括板块在内的整棵树的主要组成部分。根系保持的土壤重量是根系质量的13倍。土壤可能通过增加质量来平衡树的地上重量。