View PDF

View PDF

In recent years, various efforts have been made to expand the demand for domestic wood in Japan. As interest in environmental consciousness such as SDGs is increasing, it is conceivable to spread the product by promoting its superior environmental advantages. Wood, wood products, and wood fuels are generally recognized as environmentally friendly. However, whether environmentally friendly or not can be clarified by quantitatively evaluating its environmental impact in all processes and comparing it to other products. Therefore, in order to carry out high accuracy LCA for wood products and wood fuels, inventory data of raw materials such as logs and lumber are essential. This paper aims to provide useful information for performing LCA of logs and lumbers in Japan and explains the outlines of the manufacturing process as easily as possible. In addition, the method of collecting and processing foreground data, as well as the method of utilizing background data, is discussed through the introduction of literatures.

Wood is a common material that has been used for a long time as a building material. Wood has been mainly used for low-rise buildings, however; high-rise wooden building projects have been spreading around the world recently. These are realized by development of various engineering woods such as cross laminated timber （CLT）. Engineering wood has better mechanical properties and quality stability than ordinary lumber. However, the production process of it is more complex, and adhesives are needed to produce it unlike ordinary lumber. Therefore, environmental performance of these wooden building materials has been evaluated by LCA. In this paper, academic research papers of LCA studies of wooden building materials are reviewed. In addition, published product environment declarations （EPDs） of building materials in Japan, Europe, and the United States are reviewed, and the evaluation methods are discussed. Especially, this paper discusses issues of a biogenic carbon evaluation method, environmental impacts of production stage of wooden building materials, and impacts to human health due to formaldehyde emission from adhesives in the use stage.

Because the building industry consumes a large amount of wood materials, it is responsible for an accordingly large amount of resource consumption and waste generation, and consequently, it is responsible for the heavy environmental loads. In order to respond to urgent requirements for reduction of such heavy impacts, it is considered indispensable to take appropriate countermeasures based on data gained through the systematic analysis and evaluation of such impacts using LCA. Thus, in this article, the use of woody materials in Japanese building system and the effect of applying LCA are described. First, the actual uses of woody materials in the building and the environmental loads caused by them are described, followed by discussion as to the responsibility the same industry should bear. Then, subsequently to an overview of recent situation in the use of LCA in the building system, discussion is made on the prospective utilization of LCA as a more sustainable method for evaluating woody resources and products with focus on those used in this specific industry. Lastly, future issues are considered in line with the research objectives.

As wood can be a renewable resource under sustainable forest management, its effective use has been attracting attention as a pathway toward a sustainable society. Although wood was once used almost universally in civil engineering structures, following economic growth, the primary construction materials in Japan transitioned to concrete and steel. However, in recent years, wood has again begun to attract attention as a civil engineering material within the contexts of addressing the issue of climate change, making effective use of planted trees that are now at an appropriate age for harvesting, and promoting domestic forestry and a sustainable construction industry. To examine the environmental impacts and benefits of wood, it is necessary to apply a life cycle assessment （LCA）. However, few prior LCA studies have targeted wood use in civil engineering structures. This article overviews case studies using the LCA method to quantify the greenhouse gas （GHG） emission reductions of representative wooden civil engineering structures and discusses the life cycle GHG emission reduction potential of increasing the use of wood in such civil engineering applications in Japan in the future. In addition, perspectives for future research are discussed.

Plant-derived resources have become not just an option of raw materials, but also inevitable ones to mitigate fossils significantly. Especially, wood-derived resources are important in Japan due to the large domestic potentials. Life cycle thinking approaches are required for conversion technology options of wood-derived resources into products under research and development, demonstration test, and industrialization. In this study, the requirements of life cycle thinking for wood-derived biomass utilization are overviewed by applying bibliometric analysis into data-driven reviews of related research topics compared with expert-judged topics extracted from reports and literatures. Based on the overviewed keywords, the requirements for life cycle thinking are discussed on the definitions of system boundary, functional unit, assessment index, geographical boundaries, and application into regional system design.

Objective and Method. We compared the heating and cooling energy consumption of a house with good insulation and then with more insulation. Our target house was a well-insulated and airtight house in Nagano City. We targeted the energy saving standards of 1980, 1992, 1999, the HEAT20 G1, and the HEAT20 G2. We compared the life cycle CO₂（LCCO₂） emissions from the house with good insulation and then with more insulation in a cold district for 30 years.

Results. A house built by HEAT20 G2 standard has more CO₂ emissions until two years after construction than that by the energy saving standard of 1999. A house built by the energy saving standard of 1999 has 2.8% more CO₂ emissions than that of the HEAT20 G1 standard, and 4.5% more than that of the HEAT20 G2 standard.

Conclusions. We clarified that the CO₂ emissions from the house with more insulation was higher than that of the house with less insulation during construction. However, the CO₂ emissions from the house with more insulation was less than that of the house with less insulation from cradle to grave.

For addressing social issues through systematic design, not only the direct effects but also the indirect effects for the social issues should be taken into account in decision making. In this study, such effects of a health promotion event in Wakayama prefecture are discussed through socio-economic analysis applying input-output tables. The results show that the cost of the health promotion event consists of 64.5% organizer cost and 35.5% exhibitors cost, which was spent on labor cost, venue expenses, and educational products. These activities have a certain direct and indirect effect from various services （“Goods rental and leasing”, “Amusement and recreational services”, “Miscellaneous business services”, “Miscellaneous personal services”, and “Self-transport （freight）”）, “Printing”, and various products （“Miscellaneous wooden products”, “Miscellaneous manufacturing products”, “Miscellaneous foods”, “Miscellaneous processed paper products”, “Noodles, bread, confectionery”, and “Preserved agricultural food stuffs”）. It was also demonstrated that different contents of the exhibition have different induced effects on related industries. These results necessitate design and assessment of projects for regional circulation based on the understandings on their consequential effects on regional economy.

View PDF

View PDF

View PDF

View PDF

View PDF

View PDF

View PDF

View PDF