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Microclimatic conditions (relative humidity and temperature) were monitored in a shipment of Norway spruce (Picea abies) wood inside an intermodal container on its 66-day transport from Slovenia to Japan. In parallel, the susceptibility of Norway spruce wood to moulding fungi was determined and a dynamic vapour sorption analysis was performed. Considerable moulding developed on specimens that were exposed to a climate with relative humidity above 93%. The results of the laboratory assessment correlated with the observations of mould development in the container. The relative humidity in the container was below 93%, so there was no mould growth on the transported Norway spruce wood. [ABSTRACT FROM AUTHOR]

Wood is one of the most important construction materials and its use in building applications has further expanded in recent decades. In order to enable even more extensive and reliable use of wood in outdoor applications, factors affecting wood’s service life need to be understood. It is well known that fungal degradation of wood is predominantly affected by temperature (T) and moisture content (MC). In order to elucidate the influence of these two factors, long term monitoring of T, relative humidity (RH) and MC at four locations was carried out: a model house made of thermally modified wood in Mozirje (1), the WWII partisan hospital Franja (2), a hayrack in Pokljuka (3) and a house in the north of Slovenia in Vrba (4). The results clearly showed that fungal degradation of wood is influenced by MC and T. In addition, the influence of micro-climatic conditions on fungal decay was shown. [ABSTRACT FROM AUTHOR]

Thermal modification is the most important commercial modification procedure. Thermally modified (TM) wood has improved durability, but its performance does not meet expectations predominately under moist conditions. To reduce water uptake of TM wood, Norway spruce specimens were treated with suspensions of a natural wax by dipping impregnation (DipI) or by vacuum-pressure impregnation (VPI). Wax-treated specimens were subsequently TM at 185, 200, 215, and 230°C. Control specimens were heated up to 100°C only. Contact angle (CA), short-term and long-term water uptake, bending strength, and performance against wood decay fungi of the resulting material were determined. The results show that a combination of wax treatment and thermal modification have a synergistic effect that considerably improves hydrophobicity, reduces liquid water uptake, slows down water vapor uptake, and improves the resistance against fungal decay of the treated material. [ABSTRACT FROM AUTHOR]

The development of non-biocidal and environmentally friendly systems to protect wood against biological decay has become a high priority in recent years. In the present study the impact of an innovative modification procedure, combining two environmentally friendly modification methods: thermal modification and mineralisation, using an aqueous solution of calcium acetoacetate as a precursor, on the fungal durability of wood was evaluated. European beechwood (Fagus sylvatica) and Norway sprucewood (Picea abies) were selected as model wood species. Wood samples were treated using either a single or combination of both methods and exposed to four different fungi: Gloeophyllum trabeum , Rhodonia placenta , Trametes versicolor and Pleurotus ostreatus. The effect of the different modifications on moisture content, dynamic vapour sorption, contact angle and pH value was also evaluated. Overall, the highest durability against Rhodonia placenta , Trametes versicolor and Pleurotus ostreatus was achieved through thermal modification in both wood species, while the combination of mineralisation and thermal modification has a synergistic effect against degradation by Gloeophyllum trabeum. In the case of beechwood the mass loss decreased from 41% for native to 6% for combined modified samples. We proved that the effectiveness of different treatment against fungal decay of wood were in strong dependence of their moisture content, dynamic vapour sorption, contact angle and pH values. The role of fungi on the morphology of the wood and on crystal structure of formed carbonate was investigated using SEM-EDS analysis. [Display omitted] • Presented ecological modification of wood can be an alternative to biocides. • A significant improvement in the fungal durability of wood was achieved. • Thermal modification and mineralisation work synergistic against wood decay fungi. • The reasons for a synergistic effect of combining methods were proposed. • The mass loss decreased from 41% for native to 6% for combined modified beechwood. [ABSTRACT FROM AUTHOR]

Interdisciplinary investigations of damaged cultural heritage objects have nowadays become standard practise. Numerous techniques in various fields may generate large amounts of data, difficult to interpret. Machine learning was applied to data collected from samples of a painting to build a predictive model of potential further biodeterioration and consequent damage to the paintings. We used this strategy for a deteriorated 17th century Celje Ceiling, tempera painting in a wooden frame, covering 143 m2 of the ceiling. An interdisciplinary approach, from monitoring microclimatic conditions and wood moisture content, to examinations using UV and VIS photography, analyses of paint layers and decay products by Raman and FTIR spectroscopy, SEM-EDS, and protein binders by ELISA, was used to assess current condition of the painting. Data from 535 painting's samples were subjected to analysis by machine learning methods. Moulding, the main cause of biodeterioration, was found to be strongly influenced by the position of the painting in the room and related microclimatic conditions. The presence of a coating layer, protein binders and pigments, such as goethite, ultramarine and kaolinite, had important role in mould development as well. The painting was mainly damaged by currently non-active, presumably xerophilic Aspergillus species, as determined by microscopy, cultivation and amplicon sequencing. [Display omitted] • Four century-old tempera painting, Celje Cieling, covering 143 m2 of ceiling was analysed using a multidisciplinary approach. • Microclimatic conditions in the chamber and wood were monitored over three years. • Data obtained by painting analyses were subjected to machine learning to create a predictive model of further deterioration. • Microscopy, culture-dependent and -independent methods were used to assess microbial contamination in selected parts of the painting. [ABSTRACT FROM AUTHOR]

Simple Summary: Over the past thirty years, the thermal modification of wood has become a universally recognised and commercialised wood modification process. Thermal modifications may affect wood properties, either positively (dimensional stability and decay resistance) or negatively (mechanical properties). The combination of the impregnation of specific reagents with thermal modification may help to overcome the negative effects on wood properties. In this study, we evaluate the effect of a combination of two zwitterionic buffers, bicine and tricine, and thermal modification of two wood species (beech and spruce) against subterranean termites and their symbiotic fauna. Bicine and tricine treatments alone had a clear influence on wood mass loss and termite survival. The flagellate protist symbiotic community was affected by the treatments and responded differently to them, as a highly adaptable community. However, the combination of bicine with the thermal modification showed a negative effect on termites and their symbionts on both wood species. The combination of these different factors should be further investigated, as these results seem to be promising with regard to the enhancement of the termite resistance of wood. The majority of thermal modification processes are at temperatures greater than 180 °C, resulting in a product with some properties enhanced and some diminished (e.g., mechanical properties). However, the durability of thermally modified wood to termite attack is recognised as low. Recent attempts at combining thermal modification with chemical modification, either prior to or directly after the thermal process, are promising. Buffers, although not influencing the reaction systems, may interact on exposure to certain conditions, potentially acting as promoters of biological changes. In this study, two zwitterionic buffers, bicine and tricine, chosen for their potential to form Maillard-type products with fragmented hemicelluloses/volatiles, were assessed with and without thermal modification for two wood species (spruce and beech), with subsequent evaluation of their effect against subterranean termites (Reticulitermes grassei Clément) and their symbiotic protists. The effect of the wood treatments on termites and their symbionts was visible after four weeks, especially for spruce treated with tricine and bicine and heat treatment (bicine HT), and for beech treated with bicine and bicine and heat treatment (bicine HT). The chemical behaviour of these substances should be further investigated when in contact with wood and also after heat treatment. This is the first study evaluating the effect of potential Maillard reactions with zwitterionic buffers on subterranean termite symbiotic fauna. [ABSTRACT FROM AUTHOR]

Forests are under great pressure due to climate changes. It is forecast that the importance of Mediterranean type forests will significantly increase. Among various types of oak species, pubescent oak (Quercus pubescens) will likely gain ecological and economic importance in the region south of Alps. Although this wood species is well known, there are not much data available about chemical properties and durability. A comprehensive analysis of extractives and durability against wood decay fungi was therefore performed. The results of the chemical analysis revealed that heartwood contains up to 20% of the extractives, with considerable amounts of phenols, including a fairly high concentration of Gallic acid (GAc). Anatomical structure, with high frequency of tylosis, resulted in good water exclusion efficacy. The presence of biologically active extractives and superior water exclusion efficacy resulted in good durability, as shown by basidiomycetes tests. Based on the laboratory data, factors that determine the service life of wood were calculated. Data indicate superior performance in above-ground applications. [ABSTRACT FROM AUTHOR]

In this study, the combined effects of chemical (with tricine and bicine) and thermal treatments were investigated. The modifications which appeared in the wood structure were evaluated by infrared spectroscopy and chemometric methods (principal component analysis and hierarchical cluster analysis). After the treatment, about 6–7% of WPG was identified in treated samples, but further thermal treatment decreased the WPG to about 5%. The modifications appearing in the spectra were mostly related to increase of the intensities of the bands assigned to C O groups but also to N–H and C–N groups, with shifting of some bands to higher wavenumber values. Image 1 • The combined effects of chemical and thermal treatment on soft and hardwood were evaluated. • The effectiveness of treatment was evaluated by infrared spectroscopy and chemometric methods. • The occurrence of the reactions between the functional groups from bicine and tricine and wood structure were identified. • Softwood samples were more susceptible to chemical/thermal modification than the hardwood samples. [ABSTRACT FROM AUTHOR]

Results of the research aimed to increase the resistance of beech and thermally modified (TM) beech wood to UV-light and weathering with impregnation with commercially available nano TiO2 suspensions, originally intended to be used as UV protective coating additives, are presented in this paper. Beech wood and TM beech wood samples were vacuum-pressure impregnated with suspensions, containing around 3% of TiO2, and in one series, the specimens were at first impregnated and thermally modified afterwards. In general, resistance to UV-light, as demonstrated by visual observation and by colour measurements was increased. Contact angle of water, liquid water absorption, and water vapour sorption also importantly influence on weathering behaviour of wood and it was shown that in general, impregnation with TiO2 particles has a positive influence with this respect. Anyway, some results of this preliminary research were ambiguous, and subsequent investigations of this novel protection method are needed and planned. [ABSTRACT FROM AUTHOR]

Abstract Oak disks from pile dwellings of the prehistoric site of Gran Carro (lake Bolsena, Italy) were analysed in order to estimate wood degradation. Micro-morphological observations showed that the microbial decay could be mainly attributed to erosion bacteria. The most important physical properties, i.e. Maximum Water Content (MWC), Residual basal Density (RDb), and the calculation of the Lost Wood Substance (LWS) highlighted that heartwood (HW) was moderately preserved, with MWC values slightly higher or comparable to that of recent oak, whereas sapwood (SW) was very degraded. Thermogravimetric analysis (TGA) was tested as an alternative method for the chemical characterisation of archaeological wood. The TGA profiles were critically discussed taking into account the results of the physical and micro-morphological analyses. Potentialities and drawbacks of TGA were underlined. [ABSTRACT FROM AUTHOR]

Relevant properties of stone pine ( Pinus pinea ) wood have been only fragmentarily addressed in the past, which has been recognized as a limiting factor for its potential applications. The sorption properties, permeability to water, extractives content and durability against fungi of Pinus pinea sapwood and heartwood were therefore determined in the present research. A SEM analysis was also performed. The Meyer-Veltrup model for material resistance was used to test relevant data. The results showed that sapwood of P. pinea fits into durability class 5 (very susceptible wood), while heartwood meets the requirements of durability class 2 (durable wood), if the mass loss after fungal exposure is considered as the sole criteria for classification. Heartwood contains up to 15% of lipophilic compounds, contributing to its hydrophobicity and influencing its sorption properties. In contrast, sapwood is very permeable and hence takes up a lot of water, while heartwood, with a higher resin content, exhibits better water performance. The higher durability of stone pine heartwood against wood decaying fungi can be linked to the presence of phenolic extractives and hydrophobic properties. [ABSTRACT FROM AUTHOR]