松屬喬木側根的強度特徵對松屬防護林固土護坡作用的影響

Tensile strength of lateral roots of pine trees and its significance in slope stability under pine trees shelter-forest

周躍(Yue Zhou) ； 張軍(Jun Zhang) ； 駱華松(Hua-song Luo) ； 徐強(Qiang Xue)

《中華水土保持學報》 32卷1期 (2001/03) Pp. 29-34

https://doi.org/10.29417/JCSWC.200103_32(1).0004

摘要

喬木根系的土壤加強作用是防護林穩定土壤和保護坡面的最有效的機械途徑，其中側根的牽引效應在山地固土護坡過程中具有重要作用，其潛能與側根的抗張強度呈正相關關係。本研究構建了側根抗張強度與其牽引效應關係的數學模型，對雲南山地的雲南松、華山松和思茅松這三種代表性松林進行了分析。結果表明，三種松樹的側根抗張強度多介於5-25MPa之間，量值的高低隨根直徑的增加而降低，其中華山松的側根強度較高。三種松樹的側根在0-60cm的土壤深處有較高的分佈密度，由於具有一定的強度特徵，通過它們的牽引效應，側根使這一深度的根際土層的抗張強度提高了6.85-9.50 kPa。在20-60cm，三種松樹固土護坡能力的高低順序爲思茅松＞雲南松＞華山松。然而，松屬三個樹種的抗張強度明顯低於滇青岡、華白楊和合歡等樹種，表明松屬側根的淺層土體加固作用潛能具有局限性。

關鍵字

松屬根系 ； 防護林 ； 侵蝕控制 ； 模型預測

並列摘要

Soil reinforcement of the roots of a tree is the most significant mechanical effect of shelter-forest on soil stability and slope protection, and in mountainous areas the traction effect of lateral roots plays an important role in soil reinforcement. The magnitude of this role rises positively with the tensile strength of the roots in the soil. This study developed a mechanical model of the relationship between the tensile strength of roots and the traction effect, which was used in a pine forest. The results show that, the tensile strength of the pines mostly lay in a range of 5-25MPa, and increase negatively with the diameter of the roots. In the depth interval of 0-60cm, the density of lateral root s of the three pines are relatively high, and the roots are able to increase the tensile strength of the rooted soil by 6.85•9.50 kPa, through traction effect. Though the strength of the pine's roots and its role in increasing the strength of the rooted soil are significant, however, the strength of the pine's roots is lower than those of some broad-leaved trees. This means that, pine trees have certain limitation on their role of shallow slope stability.

並列關鍵字

root system of pine ； shelter forest ； erosion control ； model prediction