Soil Carbon Storage Trend in Various Types of Tree Stands in Shafarood Forests, Guilan Province

The current research aimed to assess the fluctuations of Soil Organic Carbon (SOC) variations in different types of forest stands along the gradient of altitude, and identify the influential factors for the its variations. Based on the random design, four plots with the surface area of 400 m2 in different stand types were established. Soil sampling up to 15cm depth in center and the corners of the each plots were taken. The biophysical attributes of trees as well as physiographical units were measured and recorded within each plot. The results of one-way ANOSIM analysis indicated the lack of similarity of SOC between pure and mixed beech stands (R≅ 0.5) and no significant difference between other stands. The results of the two-way PERMANOVA test also showed that the amount of SOC is independent of the effects of slope and the elevation gradient. The SIMPER test illustrated that the trends of soil organic carbon and soil bulk density were inverse among the stands and the gradient of altitude. However, their trends were not symmetric based on the pairwise comparisons. As a general conclusion, the fluctuations of soil organic carbon in the different types of forest stands are independent of the altitude gradient, stand type and biophysical factors, and the relative abundance of various tree species did not have a significant contribution to the variability of the soil carbon storage of the studied stands.