整株林木垂向抗拉试验研究

在土壤地形条件相同的情况下，对整株树木进行垂直拉拔试验，结果表明，树木的根系分布形态直接影响根系的垂直抗拉效果。杜鹃水平根系发达，拉拔过程中根系整体被拉出，而冬瓜杨由于垂直根系较发达，拉拔过程持续时间较长，冷杉具有垂直和侧向主根，荷载-位移（P-S）曲线表现出多峰的特征。

Experimental Study on Vertically Tensile Strength of Whole Tree

An investigation was carried out of the root systems of seven common tree species in the experimental plot. It was found that among them, the root system of Abies fabric, Populus purdomii and hododendron have ecological features that are representative of other trees; Abies fabric develop its main root system vertically with some secondary root system and Populus purdomii’s root system grows rather abundantly, while Rhododendron’s root system is characterized by a horizontal distribution of fibrous roots. We have studied the vertically tensile strength was carried out for 3 tree species on 14 tree trunks under the same soil and landform conditions. The experiments show that the shape of roots affects the vertically tensile strength of roots. Rhododendron has a developed horizontal roots, so the whole roots have been pulled out in the experiment process. Populus purdomii has a developed vertically roots, the experiment has been continued quite long time. Abies fabric has the vertical and horizontal main roots, so the P-S curve shows the figure of multi peak.