海堤林带树木根系对堤防安全影响探讨

RESEARCH ON THE INFLUENCE OF TREE ROOT SYSTEMS ON SEAWALL TO SEADIKE SAFETY

通过对苏北现有海堤防护林造林树种的根系、土壤抗冲、抗蚀及渗透性能进行了认真调查和试验测定工作。本文认为：（１）树木根系有较强的网络土壤功能，能大大提高土壤的抗冲、抗蚀性能，其抗冲、抗蚀指数随根量（尤其是细根数量）的增加而增加。（２）海堤树木根系分布有其独特性，水平根系主要由２～３根较粗侧根组成，并沿海堤走向水平伸展，而垂直伸向海堤的侧根较少。垂直根系分布深度视树种、年龄而异，一般在０．６～１．０ｍ左右，最大不超过１．ｓｍ。（３）根系集中分布范围主要限于表土层，土壤渗透性能以表土层高于底土层，各地段０～４０ｃｍ土层的稳渗系数间存在较大差异，４０ｃｍ以下底土层间无明显差异。故认为林木根系主要是增加表上层土壤的通透性，对底土层的影响较小，如采取合理的林木采伐方式，在海堤上植树不仅不影响堤防的安全，而且还能大大提高海堤防冲抗淘能力。

Based on the investigation to tree roots on seawall and tests on soil antieroding and anti-watering as well as soil seeping characteristics,the paper presentS some research results as follows (A)Tree roots have a great soil holding ability and can increase soil conservation capability the index ofsoil anti-erosion and soil anti-scouring will increase with the increase of tree root quantity,especilly,of the thinner roots thinner than 1 mm in diameter.(B)Tree roots on seawall has special distributivecharacteristics.Their horizontal roots consist of 2 to 3 main side roots which develop along the seawalland only a few smaller side roots develop toward seawall. The vertical distributive depth of tree rootsis shallower, generally, the depth is 1. 0 meter or so. The deepest one will not be deeper than 1. 5 meters.(C).The main distributive layer of tree roots on seawall is restricted in upper soil layer, the influence of tree roots on sedike to soil seeping capability is restricted only in upper soil layer and there isonly a little influence to deeper soil layer.So to plant trees on seadike will not decrease the seawall stability, but can ensure its safety. Synthesizing the research results above,We should plant more andmore tree on seawall in the future on the basis of scientific design.