Models to Estimate the Bark Volume for Larix sp. in Poland

Bark constitutes one of the main residues and by-products of the timber harvest. Therefore, in order to conduct effective forest management, it is essential to estimate the possible amount of that product, which can be obtained during the harvest process. Our objective was to develop a model to estimate bark volume and bark volume fraction (i.e., its share in the total volume of a tree). For the study, we choose larch (Larix sp.) which is a rare but valuable forest raw material in Poland. The research material was collected in northern (2 sites), central (1 site), and southern (2 sites) in Poland. In total, we obtained data from nearly 600 trees growing on oligo-, meso-, and eutrophic sites. We used the tree’s breast height diameter, height, and total volume as independent variables. Both analyzed bark parameters varied significantly with regard to location, site type, and age class. Bark volume is strongly and significantly dependent on the tree’s breast height diameter, height, and total volume. For bark volume fraction, this correlation is significant but very weak. The best results of bark volume estimation are achieved for the model with total tree volume as an independent variable. Because of the strong effect of location on bark volume estimates, it is recommended to elaborate locally-based models for this parameter determination.