Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2026
Authors
Andrea Ponzecchi Albin Lobo Claudia Cocozza Paolo Cherubini Matthias Saurer Erik Larnøy Lisbeth G. ThygesenAbstract
Broadleaf afforestation increasingly requires planting material that combines valuable wood properties with resilience to climatic stress. High heartwood content is a desirable trait in pedunculate oak (Quercus robur), but it is unclear whether selecting for it could be a trade-off with resistance and resilience to drought. We addressed this question in a 24 year old progeny trial in southern Denmark where trees were ranked by heartwood production and the 2018 drought was used as a natural stress event. Trees with contrasting heartwood content were assessed using multiple indicators of drought response, including annual ring width, vessel anatomy, wood density, and dual stable isotopes (δ¹³C and δ¹⁸O) measured separately in earlywood and latewood over a five-year period. The 2018 summer drought was of moderate intensity at the trial site, with SPEI3 approximately −1.5, but it was clearly reflected in isotopic signals, indicating that trees perceived the water deficit. In contrast, radial growth did not decline, and ring widths remained above average in 2018. Across all metrics, trees with lower and higher heartwood content showed broadly similar physiological and wood-structural responses. Within the environmental conditions and drought intensity observed in this study, our results provide no evidence for a strong trade-off between heartwood content and response to a drought of moderate severity. They therefore support, with appropriate caution, the continued consideration of heartwood content as a selection trait in breeding and afforestation programs in comparable environments.
Abstract
Wood continues to evolve as a sustainable construction material in response to global demands for circularity, climate resilience, and resource efficiency. This study develops lightweight bio-based insulation panels from wood chips, cellulose nanofibrils, and macroalgae processing residues, demonstrating enhanced fire resistance, thermal and acoustic properties. By transforming wood and marine biomass into high-value multifunctional products, the work extends the life of wood beyond traditional applications. The study highlights how innovative wood-based composites can strengthen circular bioeconomy value chains and support resilient, low-carbon buildings in an ever-changing world.
Abstract
Non-destructive and rapid analysis of adhesive penetration in engineered wood products ensures bond integrity, enabling the development of novel adhesives and quality manufacturing. The present study evaluated the X-ray densitometry method for studying the adhesive penetration in birch plywood. In this approach, it was quantified as a function of distance by measuring the X-ray density profile section where the adhesive bond-line density was above the baseline wood density. Accordingly, untreated and esterified birch veneers were pressed into plywood using both liquid and solid-type phenolic adhesives, resulting in four types of five-layered plywood of 7-8 mm in thickness. Optimization of X-ray beam attenuation through the plywood was done by preliminary trials and identified the specimen dimensions as 50 mm in height and 25 mm in width using a scanning speed of 0.5 mm min $$^{-1}$$ . The X-ray densitometry measured densities of cured phenolic adhesive to be 1150 ± 50 kg m $$^{-3}$$ and esterification-modified birch plywood to be 750 ± 25 kg m $$^{-3}$$ . These density values are consistent with gravimetric density measurements. Density profile observations indicate that both liquid and solid forms of phenolic adhesives exhibited similar levels of adhesive penetration in plywood. X-ray densitometry analysis determined a total interphase thickness ranging from 0.50 to 0.75 mm, encompassing the central adhesive bond-line and the effective adhesive penetration into both adjacent veneers. These values are comparable with those measurements obtained from microscopy imaging analysis. Therefore, X-ray densitometry could be a swift method for quantifying adhesive penetration, although further studies are needed to validate its accuracy and reliability.
Authors
Muhammad Awais Michael Altgen Kristian Hovde Liland Isak Vartdal-Gjerde Lone Ross Ingunn BurudAbstract
No abstract has been registered
Authors
Geir Wæhler Gustavsen Philip Bester Van Niekerk Jonas Niklewski Christian Brischke Gry AlfredsenAbstract
This cross-country study examineed perceptions of maintenance for coated wooden cladding in residential buildings across Norway, Sweden, and Germany. As timber cladding gains popularity in European homes, understanding expectations around cleaning, recoating, and replacement intervals becomes increasingly important. An online survey gathered responses from over 3,000 participants aged 18–89, randomly selected from representative regional panels in each country. The survey focused on the perception of maintenance practices and intervals, while also collecting data on personality traits, risk aversion, and socioeconomic background. Perceived maintenance practices for coated timber cladding differed across countries, but individual characteristics were generally more influential than national context. Most respondents accepted longer cleaning intervals than recommended, while their preferences more closely aligned with guidelines for recoating. Acceptance of replacement intervals varied markedly by country. Longer acceptable maintenance intervals were associated with a higher preference for uncoated cladding, particularly in Germany and Sweden. Younger age, urban residence, limited experience, and selected demographic and personality traits were linked to more intensive maintenance preferences.
Abstract
Abstract This study assesses the economic feasibility and environmental profile of producing Irvingia-based wood adhesives on a small scale (30 ton/year) in South Africa. A detailed techno-economic analysis was conducted including operating cost estimation and sensitivity analysis of key input variables. The estimated production costs for three adhesive formulations ranged from R157.1/kg – R318.14/kg. The average production cost was R214.62/kg and was below the typical market price of R379/kg for synthetic wood adhesives. Raw materials especially kernels and modifiers were identified as the dominant cost drivers, whereas labour and electricity had minimal impact on unit cost. A carbon footprint assessment (CFA) was performed with cradle-to-gate boundaries to estimate greenhouse gas (GHG) emissions. Two raw material sourcing scenarios were considered. They included adhesive production from kernels and adhesive production directly from whole fruits (including on-site fruit dehulling). The cradle-to-gate CFA indicates that both scenarios have similar GHG emission profiles given equivalent process conditions, with most emissions arising from energy use and chemical additives rather than feedstock transport. A review of mechanical performance from prior studies showed that these bio-based adhesives met industry standard requirements. The results demonstrate that small-scale production of Irvingia adhesives is economically viable and environmentally sustainable, making it a promising alternative to synthetic adhesives for wood composite manufacturing in South Africa.
Abstract
This study (1) determined the differences between the dynamic vapor sorption (DVS) behavior of wood subjected to light (H2O) and heavy water (D2O) vapors at matching equivalent relative humidities (RHs) and (2) developed an in-situ method for studying the transmission-mode Fourier-transform infrared (FTIR) spectra of wood subjected to increasing RHs. The D2O-subjected wood was pre-deuterated so that the hydrogen bonding of the native wood with H2O was compared with the deuterium bonding that occurs with D2O for the DVS and FTIR studies. Fibrous Scots pine sapwood particles were used for the DVS experiments, whereas FTIR spectroscopy involved Scots pine sapwood earlywood microscopic sections placed inside a small RH chamber. The sorption isotherms and hysteresis plots of H2O and D2O showed statistically non-significant differences between the solvent vapors. However, larger practical differences were observed at higher RHs, with the H2O sorption isotherms having higher “equilibrium” moisture contents. The Gibbs free energies of sorption and desorption at equilibrium, as determined from the DVS data, showed statistically significant differences, suggesting that deuterium bonding is more thermodynamically favorable. The sorption and desorption rates obtained from the DVS samples generally indicate that H2O vapor subjection progresses initially at faster rates per RH level, without significantly affecting the total experimental time. The accessibility of the hydroxy groups increased somewhat with D2O between the before- and after-isotherm scenarios. In the FTIR spectra, H2O addition led to higher peak intensities and broader hydroxy band widths due to increased RH. The FTIR spectra for the D2O case had a decrease in the hydroxy band area, particularly in the width parameter, while the intensity and width of the formed deuteroxy peak grew as RH increased. The FTIR spectra also provided evidence of a successful hydrogen-versus-deuterium bonding comparison for the DVS study, as the intensities and band widths reverted to their original states after drying using a water-vapor-subjection method like that used in the DVS. Finally, it is hypothesized that deuterated wood is less hygroscopic than native wood, despite the thermodynamic favorability of deuterium bonding.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Shumaila Khatri Hanne Kathrine Sjølie Kristina Bringedal Gedde Lizhen Huang Per Kr. Rørstad Roja Modaresi Lone RossAbstract
This report summarizes the main findings of the research conducted within the CircWOOD project during the period 2022-2026 and presents key recommendations for decision-makers towards wood reuse in the construction sector. CircWOOD aimed to enable and support a transition to a sustainable, competitive, and technologically optimized circular wood value chain through a transdisciplinary research approach. The project was carried out by five research institutions and universities, exploring technical, environmental, economic, and social dimensions in the value chain. Our research findings demonstrate potentials for wood reuse, while also highlighting a variety of practical and market-related challenges. The report presents eight key recommendations for policymakers, industry stakeholders, and other decisionmakers to drive wood reuse. Improving sorting systems and quality control for wood waste from construction and demolition activities and prioritizing deconstruction over demolition can enable reuse. Developing supporting infrastructure such as material banks, reuse centers, and logistics systems is also important. Wood reuse can create new opportunities for businesses, while continued research, better data, and AI can strengthen decision-making and support a more resource-efficient built environment.