The efficiency of Kriging and Inverse Distance Weighting methods for mapping of Juniperus trees density at Chaharbagh site, Gorgan

Regarding to importance of Juniperus sites, it is important to estimation of tree density and spatial structure of them using Geostatic. This study was conducted in Golestan province, Chaharbagh with area of 60 ha. We refined a 15×20 grid and 300 plots (45×45 m2) were measured. The number of trees with diameter at breast height (DBH) <7.5 cm were considered. The results of the variogram analysis showed that the tree density parameter had a vigorous spatial structure. First, the spherical model was fitted on the variogram. Then, the estimations and mapping were done using Kriging and IDW approaches. Cross validation results of approaches showed that the estimation of tree density was unbiased and these methods can be used for mapping spatial distribution of tree density with acceptable precision. The Kriging method with RMSE of 6.8 tree.ha-1 and 8.7% had the better performance in comparison with IDW with RMSE of 7.5 tree.ha-1 and 9.5%. So, the Kriging method is useable in ChaharBagh for tree density mapping.