Examining post-fire environmental change and succession in Canada

Wildfire is a dominant disturbance process across Canada’s forested landscapes. It consumes organic material, releases stored carbon, and alters vegetation structure, composition, and function. Within this context, fire severity emerges as an important metric because it not only reflects the extent of fuel consumption, but it also serves as a key proxy for assessing overall ecosystem impacts. As fire regimes change in response to anthropogenic climate forcing, the post-fire environment is also likely to change. In consequence, this review focuses on the post-fire environment in Canada and synthesizes various post-fire effects, including the fate of residual fuels and fire impacts on carbon cycling, soil, microclimate, and plant communities. Following a fire, the residual fuel complex evolves through biotic and abiotic processes, including decomposition and regeneration. Further, photosynthesis and net primary production initially decrease due to the loss of vegetation, while heterotrophic respiration may increase due to greater availability of dead organic matter. At surface level, wildfires alter soils in different ways, including modifying structure, chemical composition, biological activity, moisture retention, and erosion risk, with consequences for nutrient cycling and ecological recovery. Following the loss of canopy, burned forests also experience altered microclimates that are often characterized by higher near-surface temperatures and wind speed. These changes alter both radiation balance and hydrological regime, impacting stream temperature, snowpack, and seedling survival, thereby affecting site regeneration. At higher latitudes, changing microclimates can also lead to permafrost thaw. As sites recover from disturbance, regeneration and successional pathways are influenced by interactions amongst fire severity, species traits, and site conditions. Notably, future ecological trajectories may potentially become more variable in response to changing climate and fire regime, with potential regeneration failures possibly leading to the development of non-arboreal ecosystems. As wildfire activity intensifies across Canada, there is a need to address outstanding knowledge gaps, including cumulative effects and feedbacks, and to evaluate when post-fire restoration interventions may be required. Meeting these challenges is critical for forecasting ecosystem change and supporting adaptive forest management.