Carbon sequestration and emission mitigation potential of afforestation and reforestation of unproductive territories

Afforestation and reforestation can contribute to the mitigation of climate change by increasing forested areas that can actively sequester carbon dioxide from the atmosphere through photosynthesis. The purpose of this study was to assess the potential for carbon sequestration in the ecosystem and in harvested wood products, and associated greenhouse gas (GHG) emission mitigation, following the application of afforestation/reforestation strategies on unproductive lands in the Province of Quebec over an 80-year long period (2021-2101), using the Carbon Budget Model of the Canadian Forester Sector 3. Afforestation/reforestation scenarios without harvesting and scenarios based on establishment of fast-growing species such as hybrid poplar showed the greatest short-term (2020-2040) carbon sequestration potential. Over the 80-year simulation period, plantations without harvesting generated a greater potential for carbon sequestration in ecosystems; after each harvesting event, several decades were necessary to regain any ecosystem carbon loss, which could be compensated only if a proportion of the harvested wood is converted to long-lived wood products, with high substitution effects in other sectors. In the northern boreal zone of Quebec, significant mitigation potential can be expected from the afforestation of open woodlands and poorly regenerated burns, both with or without harvesting. In the southern zone, the need for better data on vegetation succession and carbon accumulation on abandoned farmlands in the absence of plantations was highlighted by this study. This study increases the understanding of carbon sequestration by plantations, and their role as a mitigation strategy to contribute to national GHG emission reduction targets and net-zero carbon objectives.