Roots spatial distribution of Carpinus betulus in lowland Hyrcanian forests (Kheyrud forest, Nowshahr)

e aim of this study was to assess spatial distribution of roots by Carpinus betulus trees in Patom district of Kheyrud forest. For this purpose, five trees at small, medium and large diameter classes were selected randomly (totally 15 trees). In order to measure root area ratio (RAR), three soil profiles were dug at both up and down sides of trees (size 50×100 cm) by wall trench method at the horizontal distance of 1, 2, and 3.5 m from tree stem (totally 90 profiles). 10 cm horizons were identified on wall trenches and all of the root diameters were measured. Finally, RAR was calculated for each soil horizon. The RAR was decreased logarithmically by increasing the soil depth. The results of ANCOVA showed significant difference between roots distribution at small, medium and large classes. The results of t-test showed that the value of the index at first, second and third trenches wall of small class at upside significantly more than down side. At medium diameter class only third trench of upside significantly more than down side. At large diameter class, first trench of upside was significantly greater than first trench of down side. The results of this study increase our information about vegetation role in stabilizing slopes and will improve the modeling of slope stability accordance to the DBH classes.