Wooden living environments are widely held to be human-friendly, warm, and relaxing. However, the scientific evidence supporting this social image is still sparse. Recently, there has been a growing desire among industry representatives, policy-makers, and consumers for scientific research that elucidates the positive influences of wood and wooden interiors in structures intended for human occupation. The aim of this review is to provide an overview of relatively recent research that examines human responses to wood in various living environments, with a focus on the methods used in such studies. We also review the methodologies used in several studies that have been conducted in related fields, such as architecture and public health, in terms of their applicability to the evaluation of wooden environments. Based on our review of the current state of research, we further consider future challenges that lie ahead in this field. These include accumulating data on vulnerable groups and individuals for a short-term exposure to wooden environments and exploring approaches to elucidate intermediate and longer-term impacts of wooden environments on health and well-being.

This paper aims to elucidate the factors related to improvement of physical properties of bamboo as a material with increasing age. In order to achieve the purpose, the temperature dependence of the dynamic viscoelastic properties in the green condition of moso bamboo (Phyllostachys pubescens) at various ages (about 40 days ～ 9 years since shooting) was measured. In addition, the content of cellulose, hemicellulose, Klason lignin, acid-soluble lignin and hot-water extractives was obtained by chemical analysis. The results obtained were as follows: the dynamic modulus of elasticity and the loss modulus of elasticity increased and their temperature dependence changed with increasing age. From the temperature dependence of tan δ, it was found that the softening temperature rose with increasing age. The Klason lignin content increased and the acid-soluble lignin content decreased with increasing age. These changes were remarkable at early ages, and the temperature dependence was still changing little by little even as the bamboo became older. These results lead to the conclusion that, in the period up to about 80 days from shooting, the physical properties of moso bamboo are affected by the amount and the degree of polymerization of lignin, and after the ratio of components becomes constant, some changes of the quality of lignin affect the physical properties of moso bamboo.

To evaluate the suitability of wood for welfare use, the impression of, and preference for mobile phones with three different outer panel materials (metal, plastic, or wood) were examined using the Semantic Differential method. The mobile phones are intended to be used as portable assistive devices for mothers of autistic individuals. The results were subjected to factor analysis using the following four factors: “durability and maintainability”, “image of material”, “quality” and “surface texture”. The following results were obtained using multiple regression analyses: 1) both favorable impression and one's interest to purchase are highly affected by the surface texture, 2) although the image of material affects favorable impression, it does not influence one's interest to purchase, and 3) stain resistance contributes significantly to one's interest to purchase, but does not affect favorable impression. It was found that the unique texture of the wood surface affects both favorable impression and one's interest to purchase; however, the image of material of the wood affects the favorable impression but does not influence one's interest to purchase.

Five-ply sugi (Cryptomeria japonica D.Don) glued-laminated timbers were manufactured using three resorcinol resin adhesives, three aqueous polymer-isocyanate resin adhesives, and a vinyl acetate-based resin emulsion adhesive (VAE). They were impregnated with wood-preservative (ACQ), and exposed under outdoor conditions with their glue-layers at level position for ten years. Block-shear tests were conducted after 1, 3, 5, and 10 years of exposure. After 10 years of exposure, significant differences were recognized for shear-strength among adhesive resins as the result of analysis of coefficient variance (AOCV). Results for pair-comparison of AOCV between adhesive resins, showed significant differences in 4 pair-comparisons and those included VAE. Standard deviations of shear-strength tend to increase with exposure year, and for VAE they were larger than for the others. Results of goodness-of-fit tests of shear-strength for normal, log-normal, 2P-Weibull, and 3P-Weibull distributions, showed that none of these forms fit VAE after 1 year of exposure. Wood-failure ratio decreased gradually with exposure duration ; however, even after 10 years of exposure, it was more than 80% regardless of adhesive resin.

The local government of Nagano prefecture, which leads the field of wooden noise barriers in Japan, has developed two types of wooden noise barriers (Japanese larch-made and Japanese cedar-made). It targeted these wooden noise barriers and concrete noise barriers to evaluate greenhouse gas (GHG) emissions throughout their lifecycle. The effect of replacing concrete noise barriers with wooden noise barriers on the reduction of GHG emissions was evaluated. The results showed that the total amount of GHG emissions, from raw material procurement to construction, by Japanese larch-made noise barriers was lower as compared to concrete noise barriers over an evaluation period of 30 years. After the service period ended, a GHG emission reduction effect by using disposed wood, steel and concrete as fuel and recycled material could be obtained. The results indicated that replacing concrete noise barriers with Japanese larch-made and Japanese cedar-made noise barriers resulted in emission reductions of 91 kg-CO_2-eq and 62 kg-CO_2-eq, respectively, for every 1 m length of the noise barrier.