Substantial carbon removal capacity of Taiga reforestation and afforestation at Canada's boreal edge.

Large-scale tree planting at Canada's northern boreal forest edge offers potential for climate change mitigation, but this capacity is uncertain due to a lack of spatially explicit models. This study quantifies the carbon removal capacity of tree planting at the northwestern boreal edge using a carbon budget model and Monte Carlo estimates. Combining satellite inventory data with probabilistic fire regimes, we simulated total ecosystem carbon under scenarios considering fire return intervals, land classes, planting mortality, and climate variables. Our results indicate that planting ~6.4-32 million hectares could sequester ~3.88-19.4 Gigatonnes of carbon dioxide equivalent over 75 years, with the Taiga Shield West ecozone showing the most potential. Even the conservative estimate is over five times Canada's annual greenhouse gas emissions, a substantial contribution to its 2050 net-zero goal. Further research is needed to refine these estimates, assess economic viability, and investigate impacts on permafrost and albedo.