Canada's northern boreal has considerable potential for tree planting related climate change mitigation solutions, considering the sparsity of trees and large portions of non-forested land at the northern forest edge. Moreover, afforestation at the northern boreal edge would enable further the observed gradual tree-line advancement of the taiga into the southern arctic, assisting forests in their migration northward while capitalizing on their carbon capture capacity. However, significant uncertainties remain about the carbon capture capacity of large-scale tree planting in the northern boreal ecozones under changing climatic conditions due to lack of spatially explicit ecozone specific modeling. In this paper, we provide monte carlo estimates of carbon capture capacity of taiga reforestation and afforestation at the north-western boreal edge using spatially explicit carbon budget modeling. We combine satellite-based forest inventory data and probabilistic fire regime representations to simulate how total ecosystem carbon (TEC) might evolve from 2025 until 2100 under different scenarios composed of fire return intervals (FRI), historical land classes, planting mortality, and climatic variables. Our findings suggest that afforestation at the north-western boreal edge could provide meaningful carbon sequestration toward Canada's climate targets, potentially storing approximately 3.88G Tonnes of $CO_{2}$e over the next 75 years in the average case resulting from afforestation on approximately 6.4M hectares, with the Northwest Territories (NT)-Taiga Shield West (TSW) zone showing the most potential. Further research is needed to refine these estimates using improved modeling, study economic viability of such a project, and investigate the impact on other regional processes such as permafrost thaw, energy fluxes, and albedo feedbacks.