Investigation of Root Tensile Strength of Trees (POPULOUS species) on the Riverbanks

The matrix of root and soil increase the soil shear resistance. Therefore trees on beech increase stability of the riverbank. In this study، the Wu model has been employed to calculate the increase shear resistance. To apply this model، determination of the root tensile strength is required. The aim of this study is to investigate the tensile strength of populous tree root and the effects of flow and slope on tensile strength. Six trees (from POPULOUS species) which grow on the river beech were selected in a distance about one km on Saimereh River in IlamProvince. Circle profile trenching method was employed to obtain characteristics. The trench was divided in four quadrants and sampling was performed in each of them. The roots were placed in 15% alcohol solution. Hundred and twenty eight root tensile tests were performed، 64. 1% of which were successful. The problem of root rupture and scrip in between the clamps were noticeable. The minimum and maximum root diameters were 1 and 7. 9 mm respectively and the average root tensile strength was 25. 9 MPa. Non parametric methods were employed for data analysis. Results show that there is no significant difference between the average root tensile strength on up and down slope and also indirect of stream. Although the effect of flow and slope on root‘s tensile strength is slight، the effect of slope is more than flow. Also، the average root tensile strength for each tree is significantly different. In conclusion، the results suggest that it is likely that the environmental conditions and genetic characteristics of trees، to effect on tensile strength.