Improving biogenic carbon modelling of harvested wood products using dynamic LCA: Assessing the climate change mitigation potential of underutilised wood

Biogenic carbon storage in harvested wood products (HWPs) used for construction applications is recognised as a key contribution to the EU’s 2050 climate goal. To quantify this climate change mitigation potential, Life Cycle Assessment (LCA) studies are increasingly moving towards dynamic LCA by accounting for the timing of biogenic carbon sequestration and release when quantifying Global Warming Potential (GWP). However, current dynamic LCA methods often rely on generic wood data and oversimplified forest regrowth dynamics, thereby overlooking important climatic domain-, species- and component-specific (e.g. bark, branches, and stem) differences. This leaves the climate change mitigation potential of inherently diverse underutilised wood, such as hardwoods, low- quality wood, and post-consumer wood, uncertain, thereby neglecting potential benefits of their incorporation into HWPs. To address this gap, the study improves biogenic carbon modelling and presents a novel GWP- biogenic framework for attributional, dynamic LCA, enabling comparative climate change impact assessments for HWPs. Making use of detailed biomass inventories, results indicate that underutilised wood resources can exhibit higher climate change mitigation benefits than commonly used softwood stems, when directed into long- lived HWPs for construction applications in Europe. Overall, the study highlights the need to couple robust biomass inventories with improved biogenic carbon modelling to provide accurate GWP-biogenic results and thereby support the role of long-lived HWPs made from underutilised wood in meeting climate change mitigation targets.