Use of wood
Wood is a versatile material, and wooden products have at all times found a wide variety of applications in our society. Being part of a national research institute, we are engaged in most aspects of wood science and technology.
Contacts
Wood being a natural material, its characteristics are derived from the growing tree, affected by silviculture and forest site. Our expertise covers the value chain from forest via breakdown or defibration, seasoning and remanufacturing to processed timber products.
Publications
To document
Authors
Andreas Treu Katrin Zimmer Christian Brischke Erik Larnøy Lone Ross Foued Aloui Simon M. Cragg Per-Otto Flæte Miha Humar Mats Westin Luisa Borges John WilliamsAbstract
Timber structures in marine applications are often exposed to severe degradation conditions caused by mechanical loads and wood-degrading organisms. This paper presents the use of timber in marine environments in Europe from a wood protection perspective. It discusses the use of wood in coastline protection and archeological marine wood, reviews the marine borer taxa in European waters, and gives an overview of potential solutions for protection of timber in marine environments. Information was compiled from the most relevant literature sources with an emphasis on new wood protection methods; the need for research and potential solutions are discussed. Traditionally, timber has been extensively utilized in a variety of marine applications. Although there is a strong need for developing new protection systems for timber in marine applications, the research in this field has been scarce for many years. New attempts to protect timber used in marine environments in Europe have mainly focused on wood modification and the use of mechanical barriers to prevent colonization of marine wood borers. The importance of understanding the mechanisms of settlement, migration, boring, and digestion of the degrading organisms is key for developing effective systems for protecting timber in marine environments.
Abstract
Surface mould growth contributes to the colour changes of outdoor exposed wood over time. Modelling mould growth can thus help visualize wooden facades’ colour development, which can improve facade design and service life. However, existing wood mould models do not consider transient wetting effects that occur outdoors due to precipitation and condensation. To address this, four mould models were evaluated using laboratory experimental data that included exposure to transient wetting. First, the models (the original and the updated VTT model, the biohygrothermal model and the mould resistance design (MRD) model) were evaluated for Scots pine sapwood. For this evaluation, the transient wetting effect was implemented in the models by using hourly wood surface relative humidity (RH), calculated from electrical resistance measurements, as input. This showed that the original and the updated VTT model gave best fit to the experimental data. However, further evaluation of these two models for more wood materials showed that the updated VTT model was sensitive to the choice of material parameters. Large discrepancies occurred when varying the material parameters in the updated VTT model. Finally, different estimates of RH were tested in the original VTT model. Using wood surface RH as input gave best fit to the experimental data, and ambient air RH gave poorest fit. Overall, the results indicate that the original VTT model is fairly reliable and can be used to predict mould growth on wooden claddings exposed to transient wetting as long as the wood surface climate is used as climatic input data.
Abstract
No abstract has been registered
Abstract
Acetylated wood is a durable and dimensionally stable product with many potential applications in exterior timber structures. Research has shown that acetylated wood can be effectively bonded by various adhesive types. However, one of the most commonly used adhesives for timber constructions, melamine urea formaldehyde (MUF), shows poor performance in combination with acetylated wood in delamination tests based on cyclic wetting and drying. The hydrophobic acetylated wood surface leads to reduced adhesion due to poorer adhesive wetting and fewer chemical bonds between the resin and the wood polymers. The use of a resorcinol-formaldehyde (RF)-based primer on the acetylated wood surface prior to the application of MUF leads to positive gluing results with both acetylated radiata pine and beech, providing significantly improved resistance to delamination. Radial penetration of the primer and MUF in acetylated wood shows higher penetration compared with untreated wood. In addition, a phenol resorcinol-formaldehyde adhesive system showed high resistance against delamination and can be used for gluing of acetylated wood.
Abstract
Miljøpåvirkning av tre sammenlignet med andre bygningsmaterialer Den norske regjeringen har satt klare mål for å redusere forbruket av fossil energi og klimagassutslipp. Byggsektoren kan bidra for å nå disse målene ved å: Bygge energieffektive bygg; Bruke materialer med lavt forbruk av grå energi (low embodied energy materials); Bruke byggematerialer som lager for atmosfærisk karbondioksid.
Abstract
This paper aimed to investigate the genetic structure (GS) of Scots pine in the northern area of its distribution range by means of seven neutral nuclear microsatellite markers. In particular, the postglacial recolonization of these areas and possible different adaptation patterns in distinct refugia were studied. The GS and diversity were assessed with seven pairs of neutral nuclear microsatellite primers. A high genetic diversity was found in the Scots pine material tested, along with a shallow GS. This pattern is typical for recolonized areas and species with large population sizes, which are connected by pollen-mediated gene flow. A STRUCTURE analysis found two genetic groups to be the most likely, one south-eastern and one north-western group that meet in Fennoscandia. This indicates that Scots pine recolonization of Fennoscandia might have taken place from two different directions (south-west and north-east). Scots pine that recolonized the area originated in at least two different refugia during the last glacial maximum. The glacial survival in distinct refugia can have led to different adaptation patterns and growth optima in the different groups as reflected in the formation of latewood content, where lineage was a significant influencing factor.
Abstract
It is recognised that flame retardant chemicals degrade and leach out of flame-protected wood claddings when exposed to natural weathering. However, the ability to survey the current state of a flame retardant treatment applied to a wood cladding, an arbitrary length of time after the initial application, is limited today. In this study, hyperspectral imaging in the near infrared to short-wavelength infrared region is used to quantify the amount of flame retardant present on wooden surfaces. Several sets of samples were treated with various concentrations of a flame retardant chemical and scanned with a push broom hyperspectral camera. An inductively coupled plasma (ICP) spectroscopy analysis of the outermost layer of the treated samples was then carried out in order to determine each sample’s phosphorus content, the active ingredient in the flame retardant. Spectra from the hyperspectral images were pre-processed with extended multiplicative scatter correction, and the phosphorus content was modelled using a partial least squares (PLS) regression model. The PLS regression yielded robust predictions of surface phosphorus content with a coefficient of determination, R2, between 0.8 and 0.9 on validation data regardless of whether the flame retardant chemical had been applied to the surface of the wood or pressure-impregnated into it. The result from the study indicates that spectral imaging around the 2400–2531nm wavelength region is favourable for quantifying the amount of phosphorus-based flame retardant contained in the outermost layer of non-coated wooden claddings. The results also reveal that the uptake of phosphorus-based flame retardant does not occur uniformly throughout the wood surface, but is to a larger extent concentrated in the earlywood regions than in the latewood.
To document
Authors
Matthew Schwarzkopf Michael Burnard Viacheslav Tverezovskiy Andreas Treu Miha Humar Andreja KutnarAbstract
Within the Slovenian region of Istria, the olive growing and oil production industry is strong. This industry has a long history and the olives grown here have high levels of biologically active compounds including a variety of phenolic compounds. Using residual materials generated by this industry in potential wood protection systems would not only valorise low-value materials and stimulate rural economies but would also provide an alternative to currently used oil-based protection systems. The objective of this study was to produce an oil treatment for wood protection and assess its efficacy in reducing leaching, weathering effects, and fungal decay. Two maleinisation techniques were used to chemically modify low-value lampante oil in an attempt to limit leaching when impregnated in wood. Pinus sylvestris (Scots pine) and Fagus sylvatica (European beech) were treated with the modified oils and underwent leaching, accelerated weathering, and decay tests. Leaching of the treatment oils was relatively low compared with other experiments and beech wood specimens treated with a direct maleinisation treatment showed improvement in performance compared to control specimens. In addition, it was found that the modified oils were not completely removed from the wood after solvent extraction indicating that they could potentially be used as an immobilisation agent in combination with other treatments thereby reducing the amount of active component of the protective agent.
To document
Authors
Callum Aidan Stephen Hill Andrew Norton Janka DibdiakovaAbstract
More than sixty environmental product declarations of insulation materials (glass wool, mineral wool, expanded polystyrene, extruded polystyrene, polyurethane, foam glass and cellulose) have been examined and the published information for global warming potential (GWP) and for embodied energy (EE) has been analysed and is presented. A peer-review literature survey of the data for GWP and EE associated with the different insulation products is also included. The data for GWP (kg carbon dioxide equivalents) and EE (megajoules) is reported in terms of product mass or as a functional unit (FU) (1 m2 of insulation with R = 1 m2 K/W). Data for some classes of insulation material (such as glass wool) exhibit a relatively narrow range of values when reported in terms of weight of product or as a functional unit. Other classes of insulation material exhibit much wider distributions of values (e.g., expanded polystyrene). When reported per weight of product, the hydrocarbon-based insulation materials exhibit higher GWP and EE values compared to inorganic or cellulosic equivalents. However, when compared on an FU basis this distinction is no longer apparent and some of the cellulosic based materials (obtained by refining of wood chips) show some of the highest EE values. The relationship between the EE and GWP per kg of insulation product has also been determined as being 15.8 MJ per kg CO2 equivalents.