Mapping forest stand and inventory according to scientific and objective parameters measured is significantly important for present and future condition of the forest stand. Using SAGA-GIS free geographical information system (GIS) software B-Spline, Multilevel B-Spline, Cubic Spline, Thin Plate Spline, Inverse Distance Weighting, Natural Neighbour, Ordinary Kiriging, Universal Kriging spatial prediction techniques, working areas’tree volume data spatial interpolation maps were generated on the basis of species and diameter class. Root mean square error and percent root mean square error (PRMSE) values of generated maps were calculated and accuracy of them were compared against species and diameter class for each technique. Two different study area were selected representing single and multiple species within a plan unit. Growing stock (volume) per hectar data in 463 forest inventory sampling points for single species plan unit and 1.317 sampling points for multiple species plan unit were used. The order of methods according to the PRMSE was as follows: MBSP<TPSP<IDW<OK<NN<BSP<UK<CSP. After then, generating stand outline maps from spatial interpolation maps by objective criteria, the ELECTRE TRI method was used.