Carbon Life Cycle Assessment on California-Specific Wood Products Industries: Do Data Backup General Default Values for Wood Harvest and Processing?

Abstract

Carbon life cycle assessments (C LCA) play a major role in greenhouse gas (GHG)-related forest management analytics for wood products and consist of several steps along a forest to disposal path. Yet, input values for wood product C LCAs frequently rely on potentially outdated generic datasets for wood product outputs and mill efficiencies. Assumptions regarding sawmill efficiencies and sawmill-specific wood product outputs have a direct and significant impact on wood product C LCAs because these variables affect the net carbon footprint of the finished product. The goal of this analysis was to evaluate how well standard wood product C LCA inputs and assumptions for the two initial wood products LCA steps (i) forest operations and (ii) wood processing represent the current state of the wood processing industry in California. We found that sawmill efficiencies and wood product outputs both support and deviate from lookup tables currently used in publications supporting the climate-forest policy dialogue. We recommend further analysis to resolve the major discrepancies in the carbon fraction stored in durable wood products and production-related emissions to improve C LCA metrics and advance forest-related climate policy discussions in California and elsewhere.