Application of Kriging and IDW methods in mapping of crown cover and density of coppice oak forests (case study: Kakareza region, Khorramabad)

This research was conducted to investigate the spatial structure to estimate the crown cover and density of a coppice oak forest in west of Iran (Loristan province) using Kriging and IDW (Inverse Distance Weighting) interpolation methods. Field sampling was performed based on a 100m×100m systematic grid using 1500 m² circular samples of. Totally, 54 sample plots were measured at 54 ha. Experimental variograms for forest stem density and crown cover were calculated and plotted using the geo-referenced inventory plots. The calculated variograms of stem density and crown cover showed medium spatial autocorrelation fitted by spherical models. Estimations were made by ordinary block (38m×38m) kriging and IDW (power=2). Cross-validation results showed that all estimations are unbiased. Therefore, Kriging and IDW are able to accurately estimate and map the crown cover and density of this kind of coppice forests.