The use of plants for protection of slopes or river embankments against water and wind erosion is spreading in civil and
environmental engineering. Naturalistic approach for slope stabilization has been more and more studied and experimented, and a
genuine discipline, that integrates traditional geotechnical engineering methods, has been created: Bioengineering. To evaluate
plants roots effect on soil shear strength and slope stability, theoretical and experimental studies about biotechnical and
mechanical characteristics are needed, to better understand soil-root interaction mechanism. This work provides indications on
mechanical strength parameters of some species of native plant roots. Tensile strength of two Mediterranean species have been
analyzed caring out a series of experimental tests. Results indicate that tensile strength of roots is influenced by many factors,
among which, the most important are root diameter, its moisture and the location where plants had grown up.