WOOD RESEARCH Volume 61, Number 4, 2016
Vlastimil Borůvka, Aleš Zeidler, and Stanislav Doubek

Impact of silicon-based chemicals on selected physical and mechanical properties of wood

This study deals with the impact of silicon-based chemicals on selected physical and mechanical properties of wood. Wood of European beech and Scots pine was the testing material used for impregnation using water glass and commercial product Lukofob EVO 50. The impact of the treatment on dimensional stability, bending strength and modulus of elasticity was tested. Wood density was also evaluated. Although the modification using silicon-based staffs resulted in a statistically significant decrease in swelling for both of the tested species, the positive effect of the treatment was accompanied by a decrease in the strength and stiffness of wood. Water glass had a stronger effect on the tested properties from the chemicals we used in our research.

WOOD RESEARCH Volume 63, Number 4, 2018
Stanislav Doubek, Vlastimil Borůvka, Aleš Zeidler, and Ladislav Reinprecht

Effect of the passive chemical modification of wood with silicon dioxide (silica) on its properties and inhibition of moulds

This work investigates how wood modification with silicon dioxide affects its selected physical and mechanical properties and resistance to moulds. Silicon mineralization can improve some of the technical properties of wood and extend the service-life of wooden structures. Silicon, which is contained in inorganic and organic-inorganic substances that are used for artificial wood mineralization or is the main component at natural wood mineralization, was used in the form of colloidal silicon dioxide and its various concentrations for pressure impregnation of beech (Fagus sylvatica) and Silver fir (Abies alba) wood samples. Following, physical, mechanical and biological properties of such modified woodswere tested together with waterlogged fir wood stored in water over a long period. Silicon-dioxide did not significantly improve properties of beech and fir woods, probably due to the hypothesis, that none covalent bonds between the silicon and the OH- groups of cellulose, hemicelluloses or lignin could be created in the cell-walls of the silicon-modified woods.

WOOD RESEARCH Volume 64, Number 5, 2019
Ondřej Schönfelder, Aleš Zeidler, Vlastimil Borůvka, and Lukáš Bílek

Impact of silvicultural measures on the quality of scots pine wood Part II. Effect of site

This study deals with the variability of wood density, compression strength and the impact bending strength within the trunk of Scots pine (Pinus sylvestris L.). The impact of the site on the examined properties was also evaluated. The tree samplers come from four different sites that are representative for Scots pine growth in the Czech Republic. From the samplers the sections representing a basal part of the trunk and a middle part of the tree were cut. The most significant influence of the site was confirmed for wood density; on the other hand, the influence of the site is ambiguous in terms of the examined strength characteristics. A decrease in the wood properties with increasing trunk height was proven for all tested properties. The highest impact of the position was observed for wood density, while the results of vertical variability in mechanical properties are not always significant (compression strength: basal 47.1 MPa and middle 45.8 MPa). A close correlation between mechanical properties and wood density was also proven.

WOOD RESEARCH Volume 64, Number 4, 2019
Ondřej Schönfelder, Aleš Zeidler, Vlastimil Borůvka, and Lukáš Bílek

Impact of silvicultural measures on the quality of Scots pine wood. Part I. effect of regeneration method

This study deals with the influence of the silvicultural measures on selected mechanical properties of Scots pine (Pinus sylvestris L.) wood in the Czech Republic. Sample trees were selected at two different localities that are characteristic of Scots pine growth, and they represent two different Scots pine regeneration methods, namely the clear-cutting and shelterwood regeneration method. We tested compressive strength and impact bending strength. The density of the wood was also evaluated as a factor influencing strength characteristics. The shelterwood regeneration method shows higher values in most of the investigated characteristics (49.3 MPa for the shelterwood method and 44.6 MPa for the clear-cutting method in the case of compressive strength); however, these differences are not significant for the processing industry. Another positive effect of the shelterwood regeneration method is the even distribution of the properties within the trunk in radial direction in contrast to clear-cutting method.