Biomass Carbon Stocks are Critical for the LUC CO2 Balance of Eucalyptus in Brazil

Eucalyptus biomass, a fundamental feedstock for Brazil’s bioeconomy, significantly impacts the direct land use change (DLUC) CO2 balance, a key factor in carbon footprint assessments. However, its climate impact is often quantified using simplified IPCC Tier 1 data. This study investigated the hypothesis that Tier 1 factors inaccurately represent carbon stocks in Brazilian eucalyptus plantations, underestimating forestry mitigation potential. A systematic literature review was conducted to develop a country-specific Tier 2 factor, subsequently integrated into the BRLUC (Brazilian Land Use Change) framework to recalculate DLUC CO2 balances for forestry across 5,569 Brazilian municipalities, considering the period of 2000 to 2019. The values calculated using IPCC Tier 1 data for tropical moist and tropical montane climates—the main regions of eucalyptus cultivation in Brazil—were 27 and 21 tC.ha-1, respectively, and changed to 42.36 tC ha-1 under Tier 2. This updated factor resulted in a positive shift in the CO2 balance for 99% of municipalities. These findings demonstrate that relying on continental-scale defaults misrepresents the carbon sequestration potential of Brazilian forestry. Transitioning to Tier 2 data is critical to improve the assessment accuracy, providing a more reliable foundation for decarbonization strategies within the global bioeconomy.