Development of stem profile, total tree volume and volume ratio equation systems for Abies nordmanniana (Stev. ) Spach. subsp. bornmülleriana in Kastamonu

Development of Stem Profile, Total Tree Volume and Volume Ratio Equation Systems for Abieş nordmanniana (Stev.) Spach. subsp. bornmülleriana in Kastamonu In this study, by using data obtained from Fir {Abies nordmanniana subsp. bornmülleriana) sample trees chosen from pure Fir stands in Kastamonu Forest Enterprise were used to determine stem profile, volume ratio and stem volume equations systems. Model performances were measured by four statistical performance criteria (Average Residuals, Average Absolute Residuals, Standard Deviation of Residuals or Precision, Percent Variation Explained). After choosing the best stem profile equation according to these statistical performance criteria, which was tested by a independent data set if it is appropriate or inappropriate for Fir stands at 0,05 significant level. Four stem profile models among eighteen models, Variable-Exponent Taper Equation (Kozak, 1988), Variable-Form Taper Function (Perez vd., 1990), Compatible Stem Profile Model (Bruce vd., 1968), Average Relative Stem Profile Model (Allen, 1993), gave the best results. However, only one of these models developed by Allen (1993) provided the best overall fit to a set of independent or validation data. The results obtained have shown that the models formulated can be used to predict stem taper and stem volume of Fir trees in Kastamonu where the data were gathered.Key Words: Stem Profile Models, Stem Taper, Stem Volume, Compatible Stem Taper- Volume and Volume Ratio Equation Systems