The physical and mechanical properties of beech wood (Fagus sylvatica L.) were determined after industrial thermal treatment in a steam atmosphere. Parallel clear uniaxial compression specimens (20 x 20 x 20 mm) were made from control and thermally treated wood, conditioned in a series from an oven dry to saturated atmosphere (20°C) and compression loaded parallel and transverse to the grain. The reduced density of thermally treated beech was reflected in the decreased stiffness and, especially, strength of wood transverse to the grain. No impact of thermal treatment on the longitudinal compression strength of wood was confirmed. Lower hygroscopicity was additionally detected with thermomodified wood. The results are important because the use of beechwood for constructions seems to be one of the most promising uses of this species in the near future, and thermal modification is one of the most promising methods for increasing its natural durability.
In European beech (Fagus sylvatica L.) and Scots pine (Pinus sylvestris L.), we studied the dynamics of wood formation on the sites on the edge of the natural range of both species with a Mediterranean climate. The research was supported by several projects. Tor this project are particularly important the results which show how the growth and quality of beech wood is changing under unfavorable conditions, which are due to progressing climatic changes also expected in the Slovenian sites.
We investigated remains of ancient Roman barge found during a preventive underwater survey in the Ljubljanica river near Sinja Gorica (between Vrhnika and Ljubljana, Slovenia). The investigations to a great surprise showed that it was made of beech (Fagus sylvatica) wood. The wood could be dendrochronologically dated with a post quem end date of AD 3. The use of beech wood, which has good mechanical properties but very low resistance against decay organisms, for ship building is rare. Due to this, we could present this ship as a good example that beech wood is generally useful for a wide range of very different products.
The use of wood in outdoor, above-ground applications is increasing in Europe. To further increase wood usage, more information related to service life and maintenance costs must be provided. Water exclusion efficacy (WEE) is one of the most important factors influencing service life and strongly correlates to wood moisture dynamics, surface properties, and hydrophobicity (WEE as a whole). WEE can be improved with modifications and hydrophobic treatments. The aim of this study was to elucidate which wood surface properties affect WEE and to note changes over time caused by artificial or natural aging. Wood samples of oak (Quercus), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies), and beech (Fagus sylvatica) were used to investigate this phenomenon. The moisture performance of the wood samples was improved with thermal modification, wax, oil, and biocide treatment. In total, 17 materials were prepared. After treatment, four different aging procedures were applied. Before and after aging, Fourier transform infrared spectra, colour, and contact angle were determined. The analysis of untreated wood based materials indicated that durability and hydrophobicity are related. Of all the treatments, wax performed the best and retained high hydrophobicity even after the most severe aging method (outdoor exposure).
Experimental and numerical analysis of a compression test carried out on samples of as received and thermally-treated beech (Fagus sylvatica L.) wood is presented. In a normal climate, samples with the dimensions of 20 x 20 x 20 mm were exposed to static compressive loads parallel and transverse to the grain. Afterwards, the test was modelled using the finite element method. It was confirmed that, after thermal modification, the wood's density decreased and the stiffness in both tested directions increased. After the thermal treatment, the strength of beech wood increased in the direction parallel to the grain and decreased in the direction transverse to the grain. Based on the comparison of experimental and numerical results, it is possible to use the hyperelastic constitutive law to reasonably model the force and displacement obtained in the compression test samples. The results are important for potential use of beechwood for constructions.