Mitigating post-fire regeneration failure in boreal landscapes with reforestation and variable retention harvesting: At what cost?

Successive disturbances such as fire can affect post-disturbance regeneration density, with documented adverse effects on subsequent stand productivity. We conducted a simulation study to assess the potential of reactive (reforestation) and proactive (variable retention harvesting) post-fire regeneration failure mitigation strategies in a 1.37 Mha fire-prone boreal landscape dominated by black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.). We quantified their respective capacity to maintain landscape productivity and post-fire resilience, as well as their associated financial returns under current and projected (RCP 8.5) fire regimes. While post-fire reforestation with jack pine revealed to be the most effective strategy to maintain potential production, associated costs quickly became prohibitive when applied over extensive areas. Proactive strategies such as an extensive use of variable retention harvesting, combined with replanting of fire-adapted jack pine only in easily accessible areas, appeared as a more promising approach. Despite this, our results suggest an inevitable erosion of forest productivity due to post-fire regeneration failure events, highlighting the importance of integrating fire a priori in strategic forest management planning as well as its effects on long-term regeneration dynamics.

Automated summary

This study conducted a simulation to assess the effectiveness of different post-fire regeneration failure mitigation strategies in a fire-prone boreal landscape. The results showed that reforestation with jack pine was the most effective strategy, while extensive variable retention harvesting combined with replanting in accessible areas showed promise. However, post-fire regeneration failure events inevitably led to a decline in forest productivity, emphasizing the importance of incorporating fire into strategic forest management planning.