以北川县3种常用造林树种柳杉、厚朴和桤木的根系为研究对象，野外全挖结合实验室单根抗拉伸试验，分析根系的分布、抗拉特性及应力-应变特征。结果表明，3个树种的根系存在较大差异，厚朴根系明显多于柳杉和桤木；3个树种根的最大抗拉力随直径的增加而增加，均呈幂函数关系；桤木和柳杉根系的抗拉强度随直径的增加有减小趋势，但相关系数偏低，厚朴根系抗剪强度在所测范围内呈波动变化；3个树种的2 mm径级和5 mm径级应力-应变曲线均为递增曲线，后者有较明显的屈服平台；相同径级下柳杉的抗拉强度最大，厚朴和桤木的抗拉强度接近，但极限延伸率均高于柳杉。%Three common afforestation species roots of Cryptomeria japonica, Mangnolia officinalis and alder were selected as the research objects in Beichuan County.By field full digging combined with laboratory single-root tensile test, we analyzed the root distribution, tensile properties and the stress strain characteristics .There is significant difference among three spe-cies, and M.officinalis root is significantly more than that of C.japonica and alder.The tensile strength of three tree root decreases as the diameter increases with power function relationship .The root tensile strength of alder and C.japonica in-creases with decreasing of the diameter with small correlation coefficient .The root shear strength of M.officinalis is in a fluctuation range.The stress strain curves of three species with 2-mm diameter and 5-mm diameter are increasing curves, and the latter are with obvious yield platform.The tensile strength of C.fortunei with the same size is maximum, but that of M.offi-cinalis and alder is the same.The ultimate elongation rate of M.officinalis and alder is higher than that of C.fortunei.
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