Development of a Life Cycle Inventory and Valuation of Greenhouse Gas Emission Characteristics of Domestic Larch Cross-Laminated Timber at the Material Stage (A1 –A3)

Purpose: The objective of this study is to establish a life cycle inventory (LCI) database for domestically produced Larix kaempferi cross-laminated timber (CLT) at the material stage (A1–A3) and to quantitatively evaluate its greenhouse gas emissions and biogenic carbon storage potential. By doing so, this study aims to provide fundamental data for the environmental assessment of domestic engineered wood products and to support quantitative decision-making for timber construction and carbon-neutral building design. Method: The functional unit was defined as 1m³ of CLT. Primary data were collected through on-site surveys and interviews conducted at a CLT manufacturing plant to identify material and energy inputs and outputs. Based on the constructed LCI and corresponding emission factors, a life cycle assessment was performed in accordance with ISO 14040 and ISO 14044. The system boundary was limited to raw material production (A1), transportation (A2), and manufacturing (A3). In addition, the amount of biogenic carbon stored in CLT was estimated using the wood content and average carbon fraction, and subsequently converted into CO₂ -equivalent values. Result: The results showed that the total greenhouse gas emissions at the material stage amounted to 224.76kg CO₂-eq/m³ , with the manufacturing stage (A3) contributing the largest share, followed by transportation (A2) and raw material production (A1). Meanwhile, the biogenic carbon stored in CLT exhibited a substantial CO₂ storage effect, partially offsetting emissions generated during the material stage. These findings quantitatively demonstrate the potential contribution of domestic engineered wood products to reducing embodied carbon in buildings.