An Investigation in to Spatial Structure of Soil Characteristics in a Beech Forest Stand Using Geostatistical Approach

To investigate spatial variability of soil characteristics in the most valuble forest stands in the northern Iran using geostatistical approach، a twenty hectare area in Experimental Forest Station of Tarbiat Modares University was considered. Soil samples were taken from pits، mounds، canopy gaps، under single trees and closed canopy positions at 0 - 15، 15 - 30 and 30 - 45 cm depths using core soil sampler (81cm2 cross section). pH and organic matter were measured in the laboratory، and then carbons to nitrogen ratio and carbon sequestration were calculated. Spatial variability for soil characteristics revealed anisotropic variogram due to the same variability of surface variogram in different depths. pH in all the depths and carbon sequestration in 30 - 45cm depth showed exponential model whereas the other soil characteristics resulted in a linear model in different layers. The results of spatial structure showed pH with medium structure in all the depths، organic matter and carbon to nitrogen ratio with pure nugget effect (non structure)، carbon sequestration in 0 - 30cm depth with weak structure and 30 - 45cm depth with medium spatial structure.