Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

Afforestation can mitigate climate change by creating new carbon sinks and increasing wood supply. However, climate change can impact the growth of trees in afforested areas and affect their characteristics, and the harvested wood products that can be manufactured from them. This study aimed to quantify to what extent the quality of the wood supply directed to primary processing is influenced by climate change and alters the carbon storage of wood products. A multi-model approach was used to estimate the carbon stocks in harvested biomass resulting from plantations of black spruce on open woodlands and hybrid poplar on abandoned farmlands in Québec (Canada) under a gradient of climate forcing projections. Results suggest that increased climate forcing negatively impacts the quality of the harvested wood product basket and influences the relative amount of lumber vs. pulpwood. However, according to our assumptions, the decay of solid wood products in landfills produced more methane emissions than paper, which may constrain their climate change mitigation potential in the absence of methane capture or flaring. The cascading use of solid wood products in bioenergy at the end of their service life significantly reduced overall emissions. This study highlights how comprehensive afforestation strategies can, in the long term, be used to maximize the carbon storage potential of harvested wood products sourced from new plantations, as long as these strategies also include better use of pulp-quality wood, improved cascading use at the end-of-life of wood products and, most importantly, the avoidance of methane emissions from landfilled wood.