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The present study analyses the moisture performance of nine wood species and wood-based materials determined in various laboratory and field trials to identify the method with the highest predictive power and determine the correlation between respective measurements. The moisture performance of wood and wood-based products has been recognised (besides inherent wood resistance) as the second most important parameter contributing to wood service life in above ground applications. Therefore, it is of great commercial importance to understand this phenomenon. In-service moisture monitoring trials can be unacceptably long, but on the other hand, they provide more realistic test conditions than laboratory tests. However, experiments in laboratory conditions enable a high level of reproducibility and are much faster than in-service tests. In order to assess the correlation between various tests, Pearson product moment correlation coefficients were calculated to determine the level of the strength of the linear relationship between the in-service and laboratory trials. Within this paper, it was attempted to identify laboratory methods suitable for quantification of moisture content during outdoor exposure.

With overall higher use of wood and wooden materials in the future, the importance of recycled wood will increase. Recycled wood is currently used for the production of wood based composites and for combustion. In the future, use of recycled wood will also be important as feedstock for biorefineries for the production of bio-based chemicals and biofuels. The present paper gives preliminary results on the feasibility of A I recycled wood (German classification, natural wood only treated mechanically) in a steam explosion and organosolv pre-treatment process. The presence of inorganic pollutants and non-wooden material in recycled wood material was investigated. The effect of recycled wood heterogeneity (e.g., variable wood species and wide particle size distribution) on performance of wood pretreatment and subsequent enzymatic hydrolysis was also evaluated. Microeconomic analysis of lignocellulosic feedstock for a biorefinery using organosolv cooking was calculated with various price scenarios and various proportions of recycled wood instead of fresh beech chips. The results show that the concentration of inorganic pollutants is higher than in fresh wood but below the limit values for polluted wood. Preliminary results on steam explosion and ethanol based organosolv cooking without an acid catalyst showed typical behaviour of softwood for recycled wood of A I quality in respect of hydrolysability, thus being a potential future raw material for sugar production. A I recycled wood can be used in a biorefinery without major problems and can significantly improve the economics of investment in an industrial scale biorefinery.

Hybrid poplar (Populus deltoides × Populus trichocarpa) and Douglas-fir (Pseudotsuga menziesii) wood specimens were densified with three variations of thermo-hydro-mechanical (THM) treatment. The THM treatments differed in the steam environment, including transient steam (TS), saturated steam (SS), and saturated steam with 1-min post–heat treatment at 200 °C (SS+PHT). The bending properties, FTIR spectra, and colour of the THM wood specimens were studied before and after exposure to two different wood decay fungi, brown rot Gloeophyllum trabeum, and white rot Trametes versicolor. The results showed that the performance of densified hybrid poplar wood was considerably poorer than the performance of Douglas-fir heartwood. The FTIR spectra measurements did not show changes in the densified hybrid poplar wood, while some changes were evident in densified Douglas-fir specimens. After fungal degradation, the most prominent changes were observed on the SS+PHT specimens. Colour is one of the most important parameter predominantly influenced by the wood species and the intensity of the densification process for both wood species, while after fungal exposure, the colour of all densified Douglas-fir specimens obtained more or less the same appearance, and densified hybrid poplar specimens resulted in lighter colour tones, indicating that the pattern of degradation of the densified and non-densified specimens are similar. The 3-point bending test results determined that the THM treatment significantly increased the modulus of rupture (MOR) and modulus of elasticity (MOE) of the densified wood specimens, while fungal exposure decreased the MOE and MOR in hybrid poplar and Douglas-fir specimens.

Copper-ethanolamine based wood preservatives are the most important products for protection of wood in use class III and IV applications. These preservatives can be applied using different procedures. One of them is dipping, a method which is predominantly used in less industrialised countries. The most important parameter, that influences the quality of this treatment, is dipping time. Influence of various dipping times on copper retention, adsorption, penetration, colour of the specimens and copper fixation was examined. In this paper copper-ethanolamine solutions of two different concentrations were utilised (cCu=0.05% or 0.25%). The results showed that longer dipping treatments resulted in higher uptakes of preservative solution, better penetrations and lower leaching of copper-ethanolamine based wood preservatives from Norway spruce wood. After one week of dipping, samples retained on average 275 kg/m3 of preservative solution, copper active ingredients penetrated on average 3 mm into the specimens, and only 2.3% of copper was emitted from wood impregnated with aqueous solution of the higher concentration, when subjected to ENV 1250 leaching procedure.

Assessment of brown rot decay is one of the most important issues within remedial treatment of attacked wood constructions. Pilodyn is a well-established tool for the assessment of density of several commercially important plantation species, therefore the authors were interested in its suitability to evaluate rate of decay as well. The Pilodyn measurements performed on Norway spruce wood exposed to several brown rot fungi clearly indicate correlations between needle penetration and mass loss.

Reducing boron leaching from impregnated wood has been one of the most challenging tasks for at least 50 years. In order to slow down the leaching of boron, aqueous solutions of boric acid were combined with liquefied spruce wood. The results clearly showed that leaching of boron from spruce wood impregnated with preservative solutions based on boric acid and liquefied wood was significantly reduced.

The combination of copper and N-methylol compounds considerably improves the performance against copper sensitive fungi (G. trabeum and T. versicolor), while the fungicidal effect against copper tolerant strain (A. vaillantii) remained insufficient. Addition of N-methylol compounds to copper solution significantly reduces leaching from wood blocks impregnated with the solution of the lowest copper concentration (cCu =0.1%), and less notably reduces leaching from wood blocks impregnated with solutions of higher copper contents (cCu=0.5%).