1,721,070 research outputs found
Correction to: Wood-water relationships and their role for wood susceptibility to fungal decay
No full textA Correction to this paper has been published: 10.1007/s00253-020-10479-
Biological durability of pine wood
Full text linkThe genus Pinus represents more than a hundred different tree species, most of them forming stems that can be commercially utilised for both timber and wood pulp industry. Pines are native to most of the Northern Hemisphere, while introduced and often naturalized in the Southern Hemisphere. The sapwood of pines is considered ‘not durable’ but generally easy to impregnate. On the contrary, the coloured heartwood of pines is difficult to impregnate and considered ‘less to moderately durable’ against decay fungi, but due to varying content and composition of extractives, both moisture performance and inherent durability vary within and between species. This study reviewed the literature to quantify the extent of variability of pine wood and its potential causes. Literature data from durability tests performed under laboratory and field conditions made it possible to compile reference factors for 26 pine species. The inter-species variation of biological durability is more prominent in above-ground exposure (0.7–14.9 times higher compared to the non-durable pine sapwood) compared to soil contact scenarios (1.0–2.4). The latter might be explained by fungicidal and hydrophobic extractives of pines, which play a more dominant role in above-ground exposure compared to soil exposure with permanent wetting.acceptedVersio
Resistance against fungal decay of Scots pine sapwood modified with phenol-formaldehyde resins with substitution of phenol by lignin pyrolysis products
Full text linkOpen-Access-Publikationsfonds 202
Fungal decay resistance, formaldehyde emission and weathering resistance of plywood modified with phenol-formaldehyde resin with partial substitution of phenol by pyrolysis cleavage products of softwood kraft lignin
No full textAbstract Wood modification by impregnation with phenol-formaldehyde (PF) resins is a promising method to improve the woods’ fungal decay resistance, weathering resistance, and dimensional stability. Recent research indicates that 30% of the non-renewable phenol may be substituted by renewable softwood kraft lignin cleavage products obtained through microwave-assisted pyrolysis. Pinus sylvestris sapwood modified with this resin has good fungal decay resistance but slightly enhanced formaldehyde emission. While these results on solid wood indicate a high potential of the method, the properties of modified plywood may differ, and the weathering resistance has not been studied. In this study, formaldehyde emission, weathering resistance and fungal decay resistance against three basidiomycetes ( Trametes versicolor , Rhodonia placenta , and Gloeophyllum trabeum ) of plywood modified with pure PF resin and PF resin with 30% substitution of the phenol by lignin cleavage products were analysed. The 30% lignin cleavage product substitution didn’t affect the plywood’s fungal decay resistance, with less than 1% initial mass loss in all modified specimens. While the decay resistance improved significantly for all modified samples compared to reference samples, weathering resistance slightly declined with phenol substitution compared to pure PF resin modification. The formaldehyde emissions of the plywood modified with both resins were in similar ranges to that of unmodified reference plywood. Overall, plywood with good properties for exterior applications may be produced even with the substitution of 30% of the phenol by lignin cleavage products, allowing for increased use of renewable resources
Changes in microstructure and stiffness of Scots pine (Pinus sylvestrisL) sapwood degraded by Gloeophyllum trabeum and Trametes versicolor – Part II: anisotropic stiffness properties
No full textFungal decay considerably affects the macroscopic mechanical properties of wood as a result of modifications and degradations in its microscopic structure. While effects on mechanical properties related to the stem direction are fairly well understood, effects on radial and tangential directions (transverse properties) are less well investigated. In the present study, changes of longitudinal elastic moduli and stiffness data in all anatomical directions of Scots pine (Pinus sylvestris) sapwood which was degraded by Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) for up to 28 weeks have been investigated. Transverse properties were found to be much more deteriorated than the longitudinal ones. This is because of the degradation of the polymer matrix between the cellulose microfibrils, which has a strong effect on transverse stiffness. Longitudinal stiffness, on the other hand, is mainly governed by cellulose microfibrils, which are more stable agains fungal decay. G. trabeum (more active in earlywood) strongly weakens radial stiffness, whereas T. versicolor (more active in latewood) strongly reduces tangential stiffness. The data in terms of radial and tangential stiffnesses, as well as the corresponding anisotropy ratios, seem to be suitable as durability indicators of wood and even allow conclusions to be made on the degradation mechanisms of fungi
Microstructure and stiffness of Scots pine (Pinus sylvestris L) sapwood degraded by Gloeophyllum trabeum and Trametes versicolor – Part I: changes in chemical composition, density and equilibrium moisture content
No full textFungal degradation alters the microstructure of wood and its physical and chemical properties are also changed. While these changes are well investigated as a function of mass loss, mass density loss and changes in equilibrium moisture content are not well elucidated. The physical and chemical alterations are crucial when linking microstructural characteristics with macroscopic mechanical properties. In the present article, a consistent set of physical, chemical and mechanical characteristics is presented, which were measured on the same sample before and after fungal degradation. In the first part of this two-part contribution, elucidating microstructure/stiffness-relationships of degraded wood, changes in physical and chemical data are presented, which were collected from specimens of Scots pine (Pinus sylvestris) sapwood degraded by Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) for up to 28 weeks degradation time. A comparison of mass loss with corresponding mass density loss demonstrated that mass loss entails two effects: firstly, a decrease in sample size (more pronounced for G. trabeum), and secondly, a decrease of mass density within the sample (more pronounced for T. versicolor). These two concurrent effects are interrelated with sample size and shape. Hemicelluloses and cellulose are degraded by G. trabeum, while T. versicolor was additionally able to degrade lignin. In particular because of the breakdown of hemicelluloses and paracrystalline parts of cellulose, the equilibrium moisture content of degraded samples is lower than that in the initial state
Exploring consumer perception of uncoated wooden cladding: a study across three European countries
Full text linkAbstract With increased focus on sustainable building materials and the growing popularity of uncoated wooden cladding, understanding consumer acceptance of aesthetic changes becomes crucial for sustainable architectural choices. This study investigated consumer acceptance of uncoated wooden cladding in Norway, Sweden, and Germany, focusing on personality traits and perceptions. Using an online survey with 3112 participants, the study found that preference for uncoated wooden cladding was similar (around 20%) across the three countries, despite differences in the prevalence of wooden cladding. A natural consequence of weathering of wood exposed outdoors is greying of the surface. The survey presented participants with images of uncoated wooden cladding with varying degrees of grey discolouration. Participants rated the acceptability of these claddings based on their preferences. Acceptance of this discolouration differed by country, Norwegians preferred intermediate-coloured panels, Swedes preferred darker panels, and Germans accepted all panels. Personality traits measured using the Big Five personality inventory and socioeconomic factors influenced preferences. In Norway and Sweden, those accepting the discolouration of uncoated wooden cladding included introverts, highly conscientious individuals, young people, females, and those with tertiary education. Additionally, in Norway and Germany, openness to experience was linked to acceptance, while strong emotional control was significant only in Norway. This study underscores the complexity of consumer preferences for uncoated wooden cladding, demonstrating that personality traits, in conjunction with cultural and demographic variables, jointly influence perception. The findings offer valuable insights for architects, builders, and policymakers seeking to advance sustainable construction practices while optimising consumer satisfaction in the housing sector.Research and innovation programme, Horizon 2020Norwegian Institute of Bioeconomy Research 50110001326
Decay hazard of wood exposed in-ground in changing climates in Germany
No full textFachagentur Nachwachsende Rohstoffe 10.13039/501100010812Norges Forskningsråd 10.13039/50110000541
Guidance for material selection in wood claddings based on end-user acceptance of maintenance and care
No full textAdler Werk Lackfabrik GmbH & Co. KGFRITZ EGGER GmbH & Co. OGFachverband der Holzindustrie ÖsterreichsForestValue RCNHORIZON EUROPE Framework Programme https://doi.org/10.13039/100018693ForestValue, FORMAS, Vinnova and SWEAForestValue, BMEL and FNRForestValue, RC
Durability of wood exposed above ground - experience with the bundle test method
Full text linkThe durability against decay organisms is an essential material property for wood in outdoor use. A jack of all trades method for above-ground wood durability testing has been sought for decades, but until now no method has found its way into European standardization. The method of choice shall be applicable for untreated and treated wood—ideally also for wood composites. It shall further be reproducible, objective, fast, easy, and inexpensive. Finally, it shall provide high predictive power. This study was aimed at a review of results and practical experience with the Bundle test method which could serve as a standard procedure for above-ground field tests of wood-based materials. The method allows for water-trapping, creates a moderate moisture-induced decay risk typical for UC 3 situations, and was found applicable for a wide range of wood materials. The method allows for rapid infestation and failure of non-durable reference species within five years in Central Europe. Based on results from Bundle tests with different modifications and performed at different locations, a guideline has been developed. The method is recommended as a suitable tool for determining the durability of various wood-based materials including modified and preservative-treated wood and can provide data for durability classificatio
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