Key points are not available for this paper at this time.
Cross-laminated timber (CLT) is an emerging sustainable construction material with the potential to replace concrete. Life cycle assessment (LCA) has been widely applied to quantify the environmental impact of CLT materials and buildings. However, current research on CLT LCA mainly focuses on softwoods, lacking reports on hardwood CLT. Despite the less frequent utilization of hardwood by CLT manufacturers, hardwood CLT is technically feasible and provides value-added uses for low-quality timber. This study developed a cradle-to-gate life cycle modeling framework to produce hardwood CLT in the eastern United States to address this research gap. The framework integrates process-based modeling of log production, lumber production, and CLT production and explores the influences of hardwood species, supply chain network, and energy sources through sensitivity analysis. The global warming impact of producing 1 cubic meter (m 3 ) of hardwood CLT ranged from 141.9 to 377.4 kilograms (kg) of carbon dioxide equivalent (CO 2 eq). The results showed that to satisfy the manufacturing requirements of CLT, lumber production caused more energy consumption and emissions than CLT production. Compared to selecting low-density hardwood species and minimizing transportation distance, increasing the use of biomass energy can more effectively reduce the overall environmental impact. Furthermore, the amount of carbon stored in hardwood CLT exceeded the carbon emitted during its production, with net carbon storage of 430.2–988.3 kg CO 2 eq per m 3 . This study provides valuable insights for the development of environmental product declarations for hardwood CLT and proposes improvement strategies to enhance the sustainability and market competitiveness of hardwood CLT.
Zhao et al. (Wed,) studied this question.