Comparison of the Accuracy of Methods for Calculating the Volume of Standing European Beech Trees

Abstract

The paper presents results of the analysis of the accuracy of calculating the volume of standing trees, calculated according to the method used in forestry practice, based on the principle of full calipering of all marked trees with the following calculation of mean height and standing volume according to the method of uniform volume curves. This volume was compared with the exact method for calculating the volume of actual removals including small wood in the beech stands of Little Carpathians in the territory of Lesy Slovenskej republiky, š.p. (Forests of the Slovak Republic, State Enterprise), branch establishment in Smolenice. The values of marked felling (standing trees) and the values of removals including logging residues left on the site will be compared and the difference expressed in percent. The difference between the values in percent is fitted with the accuracy of calculated standing volume (marked logging) established by the author of the method for calculating uniform volume curves, i.e. Halaj. A model curve is chosen by means of the directly detected value of mean stand quantity (mean height, mean diameter, age, site class etc.). The system of uniform volume curves links up with these quantities and gives volumes of individual trees for all diameter classes and corresponding heights. The method of uniform volume curves is used in Slovakia to calculate the volume of marked logging. Results of the analysis show that the volume of standing trees calculated according to the method of uniform volume curves is in reality underestimated by about 5% as compared with the actual volume of processed wood mass including logging residues left on the site. Thus, the calculation inaccuracy in forestry practice is exceeded by the above mentioned 5% as compared with the permitted deviation established through the method of uniform volume curves. Solution of this problem is a proposal submitted to the National Forest Centre in Zvolen for the elaboration of volume tables for the new ecotype of European beech.