WOOD RESEARCH Volume 61, Number 4, 2016
Pavla Kotásková, Zdeňka Havířová, Milan Šmak, and Bohumil Straka

Log buildings from the perspective of the current requirements

This contribution focuses on the verification of temperature and moisture content conditions inside perimeter walls of timber buildings as regards the temperature and humidity requirements in buildings intended for permanent residence. We assessed: a simple perimeter wall of solid timber, a wall of glued BSH profiles, a wall of an existing log building with additional thermal insulation in two options, and a sandwich log wall with a layer of embedded insulation. This study contrasts theoretical calculations with the values measured in a real buildings. The effect of the humidity changes on the strength and stability of dowelled joints is analysed.

WOOD RESEARCH Volume 63, Number 2, 2018
Horák Jiří, Kuboňová Lenka, Tomšejová Šárka, Laciok Vendula, Krpec Kamil, Hopan František, Kubesa Petr, Kysučan Zdeněk, and Ochodek Tadeáš

Change in the wood moisture dependency on time and drying conditions for heating by wood combustion

The aim of this study was to determine the drying time of firewood under the climatic conditions of the Czech Republic to decrease the moisture content to an acceptable level for combustion (under 20%). The effects of log size, outdoor/indoor trying and wood species were evaluated.

WOOD RESEARCH Volume 64, Number 4, 2019
Li W. G. and Zhang Z. K.

The effect of micro-pits texture on the coefficient of friction between wood and cemented carbide under different wood moisture content

Friction is an important factor during cutting of wood. Micro-texture has been proven to be an effective measure for the improvement of material friction performance. This paper investigates the effect of the cemented carbide surface micro-pits texture on the performance of wood cutting tools with the purpose to reduce the coefficient of friction on knife/workpiece contact zone. Birch (Betula spp.) and pine (Pinus sylvestris) were selected as the research object, the impacts of wood moisture content and the load used on the friction coefficient of different micropits structures were assessed and compared. We found that at a diameter of the micro-texture of 60 μm, the coefficient of friction can be effectively reduced at different wood moisture contents. The average friction coefficient between cemented carbide and wood surface increased with increasing moisture content below fiber saturation point (FSP). But the increase in free water quantity can lead to a more considerable decrease in the friction coefficient. At a higher working load, the value of the average coefficient of friction between the surfaces increases.

WOOD RESEARCH Volume 65, Number 1, 2020
Marcin Jakubowski, Arkadiusz Tomczak, Tomasz Jelonek, and Witold Grzywiński

Variations of wood properties of birch (Betula pendula Roth) from a 23-year old seed orchard

This work presents the results of selected wood properties in birch trees grown on a provenance experiment plot established as a seed orchard. The study concerned: basic density, oven-dry density and compression strength along the grain at a moisture content of 0% and at moisture content above fiber saturation point. Analyses were performed on 971 wood samples collected from 28 trees at the level of breast height. It was found high variability for diameter of breast height (22%) and relatively low for basic density (9%) and oven-dry density (11%). Average basic density was 446.5 kg.m-3 and average oven-dry density was 537.9 kg.m-3. The compression strength at 0% moisture content was four times higher (65 MPa) than the strength at moisture content above the fiber saturation point (16.6 MPa). Most of clones had similar properties within the limits of statistical errors, but a few clones exhibited statistically significant low value.