Achieving optimal dimensions for systematic sampling of forest using variography method in geostatistics (case study: series 5 of Safarood Ramsar forestry plan)

This study was conducted to determine the optimal systematic sampling dimensions in forest using Variogram analysis in geostatistics in Catchment Area 30, Safarood forest of Ramsar, with a total area of ​​100 ha. Sampling was done within a systematic grid (200m×150m) with randomly starting point. To determine the correct spatial correlation between specimens at short distances, from the intersection of the sides of the grid, two other samples were taken at a distance of 50m in two main directions from the central sample plot. Each piece of the sample consisted of two common-centered circular area of ​​300 and 700m2. The analysis of the selected model for fitting the experimental variogram of the total reference sample plots for the variables of growing stock and basal area/ha indicates the existence of a strong spatial structure and a significant relationship between the measured samples in the 700m2 sample plots. The existence of a weak spatial relationship between samples for basal area/ha in 300m2 sample plots indicate a weak spatial structure in these plots.