Climate change and transformation in forest fire regimes: an opportunity for the implementation of assisted migration of tree species in the Canadian boreal forest?

Abstract

Climate change is intensifying fire regimes in boreal forests, leading to ecological disruption and raising concerns about forest resilience and post-disturbance recovery. Altered fire dynamics creates novel opportunities for implementing adaptive silviculture for climate change, including assisted migration, the intentional movement and establishment of tree species or tree populations outside their current range of distribution to better match anticipated future climates. Here, we examine how the increasing frequency, severity, and spatial extent of Canadian boreal wildfires can serve as strategic windows for introducing climate-resilient tree species and genotypes. We review how fire influences the availability and suitability of post-fire sites for assisted migration, highlighting how fire-induced changes in soil abiotic and biotic properties may facilitate or hinder the establishment of relocated tree species. While fire can simplify site preparation, reduce biotic competition, and temporarily enhance soil nutrient availability, it may also degrade soil structure by consuming or altering soil organic matter and increasing soil susceptibility to erosion and dis-rupt essential mycorrhizal associations. We argue that assisted migration of tree species can be a proactive silvicultural tool when used in areas with regeneration failure or where future climate conditions are likely to exceed the tolerance limits of native species. Whilst scientific evidence remains limited on the regeneration success of migrated species and genotypes in post-fire envi-ronments, we argue for an integrated adaptation strategy that combines natural regeneration with targeted assisted migration interventions, guided by local site conditions, genetic considerations, and policy support, to build resilient boreal forests under changing disturbance regimes.