Biogenic Carbon Accounting in Wood Environmental Product Declarations: A comparison of methodologies in European and North American Wood Product EPDs

Abstract

Environmental product declarations (EPDs) are a key mechanism for reporting the environmental impacts of construction materials – including wood products. EPDs are standardized, third-party-verified documents that aim to clearly and transparently report the environmental impacts associated with production, use, and disposal of a product calculated according to standard life cycle assessment (LCA) accounting rules. Structural wood products are touted globally for their low environmental impacts relative to other fossil-intensive construction materials. EPDs are one mechanism – often used in combination with certifications, owners sourcing requirements, and others – used by the building industry to understand the relative impact of wood products. However, the environmental benefit of biogenic carbon sequestration and storage associated with forest growth and production and use of structural wood products is currently reported differently across regions according to varying accounting mechanisms for wood EPDs in different regions. As EPDs grow increasingly important in the context of global policy and trade, these differences in rules and accounting methods applied to structural wood product EPDs merit greater attention. This report dives deep into the accounting and reporting standards for structural and architectural wood product EPDs in Europe and North America with the goal of (1) identifying key challenges in comparability based on current standards and (2) highlighting the largest opportunities to increase the comparability of product category rules (PCRs) and related international LCA standards moving forward. The greatest differences between European and North American wood product EPDs stem from differences between these regional parent LCA standards for construction products: EN 15804:2012+A2:2019 (CEN, 2019) and ISO 21930 (ISO, 2017). Despite global agreement on the general framework of EPDs, inherent differences in the emissions and removals included in European and North American wood EPDs prevent direct comparison of products across markets due to their different approaches to quantification and reporting of biogenic carbon removals and emissions.