Mapping the spatial distribution of forest growth characteristics using different geostatistical methods (Case study: District no. 3, Sangdeh- Sari)

Investigation on spatial distribution of tree growth characteristics in different forest stands, has a fundamental role in assessing possible harvest planning considering potential of the stands. The aim of this study is mapping the spatial distribution of forest characteristics such as stand volume growth, diameter, growth, ingrowth) and determining the amount of tree mortality in the district three of Sangdeh region within a period of 5 years. Two methods of Ordinary Kriging (OK) and weighted Inverse Distance (IDW) interpolation were applied for mapping. For this purpose, we calculated the increment using direct measurement in 130 permanent sample plots. The results of this study showed that the mean volume increment, diameter increment, ingrowth and annual mortality were 5.65 cubic meters per hectare per year, 0.48 cm, 3.5 and 4.2 stems per hectare per year, respectively. For volume increment, the IDW method by power one and with a root mean square error 0.29 cubic meters per hectare per year, for diameter increment, ingrowth and annual mortality the ordinary Kriging method with a root mean square error 0.219 cm per year, 1.4 and 2.8 nha-1y-1 showed better results, respectively. Overall the results showed that geostatistical methods are efficient methods for mapping forest growth characteristics.