RESEARCH AND ANALYSIS Carbon Accounting in Harvested Wood Products Assessment Using Material Flow Analysis Resulting in Larger Pools Compared to the IPCC Default Method Gediminas Jasineviˇ cius, Marcus Lindner, Emil Cienciala, and Markku Tykkyl¨ ainen Summary Increasing the amount of carbon stored in harvested wood products (HWPs) is an inter- nationally recognized measure to mitigate climate change. Several approaches and tiers of methods may be used to analyze the contribution of HWP in terms of greenhouse gas emis- sions and removals at a regional and national level. The Intergovernmental Panel on Climate Change (IPCC) provides guidelines on three tiers of methods for estimating annual carbon stock changes in the carbon pool of HWPs. These tiers mostly differ by the availability of input data and the level of HWP aggregation. In this case study for the Czech Republic, we have applied the production approach and alternative tiers of accounting methods, which are described in the IPCC guidelines, including the default method (tier 2) and the most advanced method (tier 3). We used country-specific data and material flow analysis to trace the carbon flow over the entire forest-based sector, including only the domestic harvest and the primary and secondary wood products manufactured within the country. The results of this study show that the carbon stored in the HWP pool could be underestimated if simpler methods and default values nonspecific to the country are applied. At the national level, applying the tier 3 method resulted in a 15.8% higher annual carbon inflow in the pool of HWPs compared to the tier 2 IPCC default method. This means that the advanced method reveals an apparently higher carbon sink in HWPs. A documented increase of carbon storage might bring additional credits to reporting countries, and, more important, it could promote the use of long-life HWPs to mitigate climate change. Keywords: Climate-change mitigation forest-based sector harvested wood products (HWPs) contribution industrial ecology production approach wood industry Supporting information is linked to this article on the JIE website Introduction Background Through photosynthesis, forests capture carbon dioxide (CO 2 ) from the atmosphere and store carbon in biomass. Af- ter forest harvest, a significant amount of carbon is removed and could be held for decades in harvested wood products (HWPs) (Anderson et al. 2013). In the last decades, Euro- pean forests have removed more carbon from the atmosphere Address correspondence to: Gediminas Jasineviˇ cius, European Forest Institute, Sustainability and Climate Change Unit, Yliopistokatu 6, Joensuu 80101, Finland. Email: gediminas.jasinevicius@efi.int; Web: www.efi.int © 2017 by Yale University DOI: 10.1111/jiec.12538 Editor managing review: Stefanie Hellweg Volume 00, Number 0 than the amount that was released through burning or decom- position of biomass (Nabuurs et al. 2013; Goodale et al. 2002). It is estimated that European Union (EU) forests and the forest sector currently produce an overall climate-mitigation impact that amounts to around 13% of the total EU emissions (Nabuurs et al. 2015). Approximately 10% of this carbon might be stored in HWPs (Pilli et al. 2015). The use of wood is also associated with lower emissions of CO 2 and other pollutants when com- pared to alternative material (Gustavsson et al. 2006; Sathre www.wileyonlinelibrary.com/journal/jie Journal of Industrial Ecology 1