The function of buttress roots: a comparative study of the anchorage systems of buttressed (Aglaia and Nephelium ramboutan species) and non-buttressed (Mallotus wrayi) tropical trees
The function of buttress roots: a comparative study of the anchorage systems of buttressed (Aglaia and Nephelium ramboutan species) and non-buttressed (Mallotus wrayi) tropical trees
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DOI：
10.1093/jxb/48.9.1703
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发表时间：
1997-09
影响因子：
6.9
通讯作者：
M. Crook;A. R. Ennos;J. Banks
中科院分区：
文献类型：
--
作者：
M. Crook;A. R. Ennos;J. Banks
通过将根系形态研究与一系列锚固试验相结合，对成熟支撑树 Aglaia 和 Nephelium 以及非支撑树 Mallotus wrayi 的锚固力学进行了研究。两种类型都具有直根，但只有扶壁树具有从扶壁末端分枝的沉根。有支撑树木的锚固强度几乎是无支撑树木（4.9 kNm）的两倍（10.6 kNm），并且最大力矩在较低角度产生。在扶壁树中，背风扶壁被推入土壤，然后弯曲并最终折向其尖端，而迎风扶壁则从土壤中拔出，或者如果它们具有下沉根则分层。主根在土壤中迎风旋转。相比之下，在无支撑树木的破坏过程中，主根同时向背风方向移动和弯曲，迎风根被拔出土壤，而背风侧根则简单地弯曲。沿扶壁的应变比沿无扶壁树木的侧向的应变高得多。这些结果表明，扶壁在拉伸和压缩作用下都起作用，并且比无扶壁树木的薄侧墙对锚固的贡献大得多。扶壁的相对贡献是通过进行一系列进一步的锚固测试来确定的，在这些测试中，有扶壁的树木和无扶壁的树木在所有侧枝都被切除后都被拉倒。因此，这些树仅由主根固定。两种类型的破坏与完整的无支撑树木相似，并且它们彼此具有相似的锚固强度，均为 4 kNm，约为完整无支撑树木的 80%，但仅为完整无支撑树木强度的 40%。因此，扶壁贡献了扶壁树木约 60% 的锚固力，比无扶壁树木的薄侧墙产生的锚固力多出约六倍。
The anchorage mechanics of mature buttressed trees of Aglaia and Nephelium, and of non-buttressed Mallotus wrayi have been investigated by combining a study of the morphology of their root systems with a series of anchorage tests. Both types possessed tap roots, but only buttressed trees possessed sinker roots, which branched from the ends of the buttresses. The anchorage strength of the buttressed trees was almost double (10.6 kNm) that of the unbuttressed ones (4.9 kNm), and the maximum moment was generated at lower angles. In buttressed trees, the leeward buttresses were pushed into the soil before bending and eventually breaking towards their tip, whilst the windward buttresses pulled out of the soil or delaminated if they possessed sinker roots. The tap root rotated in the soil to windward. In contrast, during failure of unbuttressed trees the tap root both moved and bent towards the leeward, the windward roots were pulled out of the soil, and the leeward laterals simply buckled. Strains along buttresses were much higher than along the laterals of unbuttressed trees. These results suggest that buttresses act in both tension and compression and make a much larger contribution to anchorage than the thin laterals of non-buttressed trees. The relative contribution of the buttresses was determined by carrying out a further series of anchorage tests in which both buttressed and unbuttressed trees were pulled over after all their laterals had been cut away. These trees were therefore only anchored by their taproot. Failure of both types was similar to intact unbuttressed trees, and they had similar anchorage strengths to each other, 4 kNm, around 80% of the value for intact non-buttressed trees, but only 40% of the strength of intact buttressed trees. Buttresses therefore contribute around 60% of the anchorage of buttressed trees, producing around six times more anchorage than the thin laterals of unbuttressed trees.