BIOGENIC CARBON FOOTPRINT CALCULATOR FOR HARVESTED WOOD PRODUCTS BACKGROUND DATA & CALCULATIONS

The report outlines a methodology for calculating the biogenic carbon footprint of harvested wood products, moving away from the common assumption of carbon neutrality. It introduces the GWPbio approach, which accounts for the time lag between carbon emissions from harvesting and the subsequent sequestration during forest regrowth. The framework separates the impact into the 'forest carbon gap' (GWPbio, forest) and the benefits of delayed emissions through product storage (GWPbio, product), while also incorporating fossil carbon footprints. The methodology utilizes the Bern carbon cycle model to simulate atmospheric CO2 decay and provides specific growth and decomposition parameters for boreal forest (Norway spruce), Douglas fir, and Loblolly pine.

• The document argues that the common assumption of carbon neutrality for forest products is flawed because it ignores the time lag between wood removal and regrowth, which can lead to a temporary increase in atmospheric CO2 and impact radiative forcing.
• The GWPbio approach is used to measure the global warming potential of CO2 pulses from biomass combustion by accounting for forest regrowth and other dynamic processes, resulting in a value that typically ranges from 0 for annual crops to 0.96 for a 100-year rotation period with a 20-year time horizon.
• The total global warming impact of forest biomass is calculated by summing the biogenic carbon emissions and sinks (considering both the forest carbon gap and product storage time) and the fossil carbon footprint of the value chain.
• The methodology distinguishes between two reference systems for calculating the forest carbon gap: a 'Net zero' reference, which assumes a steady state and only accounts for physical emissions and uptake, and a 'Foregone sequestration' (FS) reference, which considers the burden of avoided continuous carbon accumulation if the forest were not harvested.
• Carbon storage in wood products provides a climate benefit by delaying CO2 release; for a 100-year time horizon, a 20-year storage period results in a GWPbio, product factor of -0.16, while 100-year storage results in -1.00.
• The calculator assigns specific lifetimes to different product categories to determine storage benefits, such as 50 years for building materials (sawn timber, plywood), 16 years for furnishing and other building materials, and 1 year for packing materials and structural support materials.

APA

Gmünder, S., Zollinger, M., & Dettling, J. (2020). BIOGENIC CARBON FOOTPRINT CALCULATOR FOR HARVESTED WOOD PRODUCTS BACKGROUND DATA & CALCULATIONS. WWF International. https://www.worldwildlife.org/documents/431/8ac6an0ydo_Biogenic_Carbon_Footprint_Calculator_Methodological_Report_July2020_Quantis.pdf

Chicago

Gmünder, Simon, Michele Zollinger, and Jon Dettling. BIOGENIC CARBON FOOTPRINT CALCULATOR FOR HARVESTED WOOD PRODUCTS BACKGROUND DATA & CALCULATIONS. WWF International, 2020. https://www.worldwildlife.org/documents/431/8ac6an0ydo_Biogenic_Carbon_Footprint_Calculator_Methodological_Report_July2020_Quantis.pdf.

Wikipedia

{{cite report |last1=Gmünder |first1=Simon |last2=Zollinger |first2=Michele |last3=Dettling |first3=Jon |title=BIOGENIC CARBON FOOTPRINT CALCULATOR FOR HARVESTED WOOD PRODUCTS BACKGROUND DATA & CALCULATIONS |publisher=WWF International |date=July 2020 |url=https://www.worldwildlife.org/documents/431/8ac6an0ydo_Biogenic_Carbon_Footprint_Calculator_Methodological_Report_July2020_Quantis.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{gmnder2020biogenic, author = {Gmünder, Simon and Zollinger, Michele and Dettling, Jon}, title = {{BIOGENIC CARBON FOOTPRINT CALCULATOR FOR HARVESTED WOOD PRODUCTS BACKGROUND DATA \& CALCULATIONS}}, institution = {WWF International}, year = {2020}, month = jul, url = {https://www.worldwildlife.org/documents/431/8ac6an0ydo_Biogenic_Carbon_Footprint_Calculator_Methodological_Report_July2020_Quantis.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }