Impact of power line corridors on carbon stocks of upland forests in eastern Canada.

AIM: Hydroelectricity is considered a renewable energy source with low greenhouse gas emissions. However, little attention has been given to the impact of the construction and maintenance of power line corridors on soil and vegetation. This study assessed the effect of power line corridors on terrestrial carbon pools in upland forests across a 750-km gradient from deciduous forests to open-canopy taiga in Quebec (Canada). METHODS: Quantification of ecosystem carbon pools (live biomass, dead organic matter and soil) was carried out using transects of plots located in: i) the power line corridor, ii) the forest located at 20 m from the corridor edge (forest edge), and iii) the forest located at 60 m from the corridor (interior forest, considered as a control). RESULTS: Ecosystem carbon stocks were significantly lower in the corridors, with reductions of 36-133 Mg of C ha-1 compared with interior forests. Yet, corridors still stored substantial carbon (average of 108.5 ± 13.7 Mg of C ha-1). While biomass of trees and shrubs was significantly reduced in the corridor compared with interior and edge forests, total soil carbon stocks (which varied from 80.11 to 169.91 Mg of C ha-1 across bioclimatic domains) were similar between corridors and forests. We also observed similar carbon stocks between edge and interior forests, suggesting that the influence of power line corridors is not noticeable at 20 m and beyond in adjacent forest ecosystems. CONCLUSION: Our study improves the quantification of carbon storage across forested landscapes and the GHG footprint of hydroelectricity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s11104-026-08978-7.