COMPONENTS OF TREE STABILITY IN SITKA SPRUCE ON PEATY GLEY SOIL
COMPONENTS OF TREE STABILITY IN SITKA SPRUCE ON PEATY GLEY SOIL
复制标题
DOI：
10.1093/forestry/59.2.173
复制
发表时间：
1986-01-01
期刊：
影响因子：
2.8
通讯作者：
COUTTS, MP
中科院分区：
文献类型：
--
作者：
COUTTS, MP
20米高的树木的稳定性进行了调查，拉他们与绞车。股骨柄基部的转动力矩被分解为两个分量，一个是由于施加的力，另一个是由于股骨柄和冠部的水平位移重量。根系的垂直位移进行了测量，并观察了土壤周围和下面的根土壤板的渐进故障。当树木从树冠区域拔出时，当树冠偏离c。4 m水平，当所施加的力只有约70%，所需的连根拔起。当施加的力在茎基部达到最大转动力矩时，许多根已经折断，冠挠度为c。8 m的根拔力，茎和冠的偏转重量对根拔力有很大贡献。通过在一系列切割或破坏根部和土壤的过程中反复拉动树木，锚固件提供的总阻力转动力矩被分解为以下分量：土壤阻力（由下面和根部系统处的土壤提供的对连根拔起的阻力）; ii.在迎风周边上的张力下放置的根的阻力; iii.所述根土板的重量;以及iv.背风面铰链处的抗弯性。这些组成部分的重要性各不相同的树木和改变过程中连根拔起。在锚固初期，土阻力占主导地位，但当锚固力引起的弯矩最大时，锚固力的各分量大小依次为迎风根>自重>铰>土阻力。迎风根在这些浅根系统中对锚定的主要影响突出了干扰其横向发展的特征的重要性，例如由间隔耕作产生的犁沟。
The stability of 20 m tall trees was investigated by pulling them over with a winch. The turning moment at the stem base was resolved into two components, one due to the applied force, and the other to the horizontally displaced weight of the stem and crown. Vertical displacement of the root-system was measured and observations made of the progressive failure of the soil around and underneath the root-soil plate. When trees were pulled from the crown region, the soil failed when the crown had deflected c. 4 m horizontally and when the applied force was only about 70% of that required for uprooting. By the time that the maximum turning moment at the stem base due to the applied force had been reached, many roots had broken, crown deflection was c. 8 m and the deflected weight of the stem and crown made a substantial contribution to the uprooting forces. By repeatedly pulling trees during a sequence of cutting or breaking the roots and soil, the total resistive turning moment afforded by the anchorage was resolved into the following components: i. soil resistance (the resistance to uprooting afforded by the soil underneath and at the root system); ii. the resistance of roots placed under the tension on the windward perimeter; iii. the weight of the root-soil plate; and iv. resistance to bending at the hinge on the leeside. The importance of these components varied between trees and changed during the course of uprooting. Soil resistance was the largest component in the early stages, but when the turning moment due to the applied force was maximal, the components of anchorage were in the order windwards roots > weight > hinge > soil resistance. The major effect of the windward roots on anchorage in these shallow root systems highlights the importance of features which interfere with their lateral development, such as the furrows produced by spaced ploughing.