The Italian forest carbon sink: historical evolution and future projections under alternative harvest scenarios.
BACKGROUND In 2023, forests offset approximately 9% of total GHG emissions in the EU-27, with Italy accounting for about 20% of these offsets. Historical felling rates, in Italy, are highly uncertain, with a ± 50% confidence interval. In this study, we used a forest carbon inventory model, scaled at regional level, to assess the overall impact of the harvest uncertainty on the Italian forest carbon (C) sink. The analysis included most recent information from the literature and an ancillary assessment of the harvested wood product mitigation potential. Based on this assessment, we estimate the evolution of the forest C sink to 2070, under different harvest scenarios defined by an increasing felling rate relative to the net annual increment estimated by the model on forest area available for wood supply. RESULTS Comparison of our results with the Italian GHGI data shows an overall good fit with the living biomass sink, but significantly higher removals by the dead organic matter pool. For the historical period, the modelled total C sink increases from -40 Tg CO2 yr-1 in 2005 to -55 Tg CO2 yr-1 in 2023. The future forest C sink varied between -76 Tg CO2 yr-1 and -16 Tg CO2 yr-1 by 2070, corresponding to the lowest (0.10) and highest (0.90) felling to net annual increment ratios, respectively. Our analysis confirms that the contribution of harvested wood products to the total C sink is negligible, as the Italian forest sector predominantly channels timber extraction into energy production. CONCLUSIONS Between 2005 and 2023, the impact of harvest uncertainty on the total forest C sink averaged 11 Tg CO2 yr-1, representing about ± 23% of the C sink associated with the average harvest reported in the literature for the same period. By simulating the theoretical forest C sink dynamics under different felling rates, and by excluding any possible impacts of climate change on current growth conditions, our study provides a long-term assessment of wood production potential versus carbon storage capacity. This bottom-up modelling framework aligns with the New EU Forest Strategy and can serve as a model for other European countries.