Impact of Storage Conditions on Shear Strength of Beech (Fagus sylvatica L.) and Sessile Oak (Quercus petraea (Matt.) Liebl.)

Peter Vilkovský,Igor Čunderlík,Ivan Klement,Tatiana Vilkovská

doi:10.3390/f12081025

Abstract

The structure of a bark as a component of a living tree is completely different from wood. Different structures significantly influence the physical and mechanical properties of the bark. In the processing of logs, it is in most cases necessary to separate the bark from the wood. Problems can arise mainly in the pulp and paper industry. The research focused on the impact of storage conditions on shear strength, showing that the value of shear strength decreased remarkably due to the storage. A decrease in strength can mainly be explained by the changes in the moisture content of bark, remarkably affected by the surrounding environment (climate). The research showed that three months of storage seemed to be the most appropriate and effective period for removing the bark in the case of beech logs and that a storage time of up to five months was the best in the case of oak logs.

Highlights

Debarking is a process that significantly affects other processing operations in the wood processing industry
The aim of this work was to discover the effect of storage on the value of the shear strength for oak and beech logs
The shear strength for oak logs during the growing period had an average value of about 0.24 MPa (July) and during the dormant period ranged from 0.14 MPa (December) to 0.30 MPa (August)

Summary

Introduction

Debarking is a process that significantly affects other processing operations in the wood processing industry. Debarking of logs with a lower temperature is more complicated due to a stronger bark adhesion and greater cohesiveness to the wood. The authors assessed the shear strength at the wood/bark interface in the debarking process in a drum debarker used mainly in pulp and paper production [1,4,5]. Many authors [1,5,6,7] in their study found that the moisture content was the most important factor of wood/bark adhesion. Based on the study [5], it can be stated that the lowest values of the shear strength at the wood/bark interface were measured in the case of fresh logs. The studies of several authors [1,4,8] were aimed at monitoring the effect of storage time on log wood/bark adhesion. [4] claimed that the infringement of inner bark occurred mainly on dried logs

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