Ukrainian Journal of Forest and Wood Science

Because of adoption in Ukraine harmonized with European standards methods for roundwood volumes estimation a demand for improving a regulatory base for timber volume estimation has risen. For that reason, the paper discusses the issues related to application of mathematical model of stem taper for calculation of merchantable volumes of common oak logs. The research is based on six sample plots established during harvest operation in premature and mature oak stands where 40 sample trees where selected and measured. We have found that the form of oak stems rather variable in a butt section and in upper sections between 0.5 to 0.9 of total stem height. We selected A. Kozak (2004) taper equation as the most precise among other variable-exponent equations. The accuracy for total stem volume prediction using this model is estimated to be about 7 %. To estimate merchantable timber volumes we have developed model to predict diameters along stem inside bark. The mean root square error for roundwood volume calculation is assesses to be 10 %. As a result of the study, a novel approach for individual tree volume estimation has been proposed. 

taper equation, merchantable timber, volume