The demand for wood has increased in recent years due to new technical possibilities and environmental concerns. This paper provides an analysis of the factors that affect the use of wood in the construction sector, and an assessment of their importance in individual countries and for groups of stakeholders. The study covers the technical, societal, political, economic, and gender aspects of wood construction, with the aim of increasing global understanding regarding national differences, the current situation, and the potential for further development. The subject was investigated using a survey, and the most important opportunities for and barriers to growth in the use of wood in the construction sector were selected, following a statistical analysis. The results indicate strong regional and cultural differences regarding the acceptance of some of the opportunities and barriers related to the development of wood construction. The findings indicate that there is a need to promote wood construction based on its technical and economic benefits rather than its societal ones. On the other hand, the current societal barriers should be addressed as a priority, together with the establishment of common and harmonized policies. The results of this study, therefore, will contribute to the generation of regional-sensitive information that can be useful for policymakers when updating the building codes in their individual countries.

Thermally modified wood (TMW) is widely used in outdoor applications due to its advanced properties towards weathering stresses. Although the structure changes of TMW from weather factors have been reported, investigation of the quantitative analysis of water states and cell wall structure of TMW after weathering is limited. In this work, the amount of bound water, fiber saturation point (FSP), cell wall pores, and free water distribution of thermally modified Scots pine, Norway spruce, and European ash were measured before and after a 2-year natural weathering via NMR relaxometry, cryoporometry, and magnetic resonance imaging. The results show that weathering increased T₂ relaxation time of lumens, indicating the degradation of tracheids and vessels, especially in TMW compared to unmodified wood. The amounts of bound water, FSP value, and cell wall pores were increased after weathering; however, an increase in thermal modification intensity resulted in lower FSP and limited the increase in number of pores. In summary, TMW showed better performance than unmodified wood after weathering.

Ways to long-term storage of carbon molecules captured as CO₂ from atmosphere are looked for. Timber structures act as carbon storages and timber construction is sometimes claimed as a solution to mitigate climate change. This article attempts to estimate (a) the volume of carbon stored in wooden structures of new buildings annually, and (b) the role of new wooden buildings as a compensator of human-caused annual CO₂ emissions in Finland and globally. Annual share from the total CO₂ emissions stored in wooden buildings is called building sink effect (BSE). The BSE was 0.61 in Finland in 2017, and global BSE is even smaller. In order to achieve a global BSE of 1%, approximately 450 million m³ of wood products, corresponding to 85% of the global production of lumber, all structural engineered wood and construction logs, should be long-term stored in buildings. New wooden buildings have almost indistinguishable mitigative influence on annual CO₂ emissions. However, timber construction is an important factor in a strategy towards more climate smart future, and substitution effects multiply the effects of physical carbon storages. Still more powerful actions, such as emission cuts or reforestation, have to be implemented to see real climate effects.

Circular economy may play a key role in the future success of modified wood products. The European Union (EU) aims toward a circular economy, i.e. increasing resource efficiency by waste minimization in production processes, cascade uses of materials, elimination of landfill wastes, and maximizing the value of raw materials. The policy has great expected impact across all sectors, and will influence countries with strong wood modification industries, such as Finland, Germany, Norway, and the Netherlands. It also means considerable economic efforts and sets transformation challenges to the societies and industries. Challenges have country-wise differences depending on production structure, environmental circumstances, local policies and regulations, as well as economic resources. This paper is an outlook of the renewed waste legislation in the EU, based on which it assesses the possible impacts of circular economy development on the future of wood modification. One of the key indicators for resource efficiency is € kg⁻¹, which allows pursuing increased efficiency by minimizing material input (and waste) and/or by maximizing the value. In the case of modified wood, both of these approaches may be considered market opportunities, while the key challenge and the consequent need for action relate to improved waste management.

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova–Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH–urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova–Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340–474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

All-cellulose composites (ACCs) are manufactured using only cellulose as a raw material. Biobased materials are more sustainable alternatives to the petroleum-based composites that are used in many technical and life-science applications. In this study, an aquatic NaOH-urea solvent system was used to produce sustainable ACCs from wood-based woven textiles with and without the addition of TEMPO-oxidized nanocellulose (at 1 wt.-%). This study investigated the effects of dissolution time, temperature during hot press, and the addition of TEMPO-oxidized nanocellulose on the mechanical and thermal properties of the composites. The results showed a significant change in the tensile properties of the layered textile composite at dissolution times of 30 s and 1 min, while ACC elongation was the highest after 2 and 5 min. Changes in hot press temperature from 70 °C to 150 °C had a significant effect: with an increase in hot press temperature, the tensile strength increased and the elongation at break decreased. Incorporating TEMPO-oxidized nanocellulose into the interface of textile layers before partial dissolution improved tensile strength and, even more markedly, the elongation at break. According to thermal analyses, textile-based ACCs have a higher storage modulus (0.6 GPa) and thermal stabilization than ACCs with nanocellulose additives. This study highlights the important roles of process conditions and raw material characteristics on the structure and properties of ACCs.