Original scientific paper

https://doi.org/10.5552/crojfe.2023.1641

Double Bark Thickness Estimation Models of Common European Broadleaved Species for Harvester Timber Volume Estimation in Czechia

Martin Jankovský ; Czech University of Life Sciences Prague Faculty of Forestry and Wood Sciences Kamýcká 129 165 00 Praha – Suchdol CZECH REPUBLIC
Jiří Dvořák ; Czech University of Life Sciences Prague Faculty of Forestry and Wood Sciences Kamýcká 129 165 00 Praha – Suchdol CZECH REPUBLIC
Radim Löwe ; Czech University of Life Sciences Prague Faculty of Forestry and Wood Sciences Kamýcká 129 165 00 Praha – Suchdol CZECH REPUBLIC
Pavel Natov ; Czech University of Life Sciences Prague Faculty of Forestry and Wood Sciences Kamýcká 129 165 00 Praha – Suchdol CZECH REPUBLIC
Ondřej Nuhlíček ; Czech University of Life Sciences Prague Faculty of Forestry and Wood Sciences Kamýcká 129 165 00 Praha – Suchdol CZECH REPUBLIC

Abstract

The share of the annual volume of harvester-produced timber in Czech forest bioeconomy has
increased in the last decades. To estimate under-bark timber volume, harvester systems allow
choosing between two different bark deduction models – diameter band (DBM) and linear
model. However, linear models were not calibrated for the conditions of Czech forestry. Therefore,
the objective of this research was to develop, for local conditions in Czechia, linear functions
for estimating the double bark thickness of two groups of broadleaved species (beech and
oak) and to test their viability based on real harvest data. To create the linear functions, official
Czech cubing tables were used. Data from real harvests were gathered from fifteen harvesters.
A sample containing 4995 logs belonging to the beech group was analyzed using descriptive
statistics and the Paired Wilcoxon tests. The mean double bark thickness for beech group was
15.1 mm (polynomial and linear model). For oak group, it was 15.48 mm (polynomial) or
15.49 mm (linear). The results of real harvests for beech group revealed that the mean double
bark thickness estimated by the polynomial function was 7.08 mm. The linear function estimates
were closer to the value estimated by the polynomial (6.84 mm) than DBM estimates
(6.68 mm). Therefore, we can state that the newly developed linear models can be used in
fully mechanized harvesting instead of manual bark deduction methods in Czechia.

Keywords

linear modeling, diameter band bark deduction model, beech under-bark volume estimation, oak under-bark volume estimation, non-wood forest products, forest bioeconomy

Hrčak ID:

290877

URI

https://hrcak.srce.hr/290877

Publication date:

13.1.2023.

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