Understanding ecological contexts for active reforestation following wildfires

To forestall loss of ecological values associated with forests, land managers need to consider where and when to prioritize active reforestation following major disturbance events. To aid this decision-making process, we summarize recent research findings pertaining to the Sierra Nevada region of California, USA to identify contexts in which active reforestation or passive recovery may best promote desirable post-fire ecological trajectories. Based on our synthesis, we suggest conceptual frameworks for assessing landscape conditions and determining areas that may be the highest priorities for tree planting to avoid persistent loss of conifer forests. Field studies have shown that some large patches of high severity burn can have relatively low levels of natural regeneration, especially among desired pine species. The accumulation of fuels and competition with shrubs and resprouting hardwoods may hinder the reestablishment of mature conifer trees. However, severe fires could also play a restorative role, by promoting non-conifer forested communities, such as meadows, shrubfields, and open forests with significant hardwood components. Such communities were historically rejuvenated and maintained by fire but have been replaced by conifer forest due in part to fire suppression. Reforestation in such areas may run counter to restoring ecological function and the ecosystem services that are provided by non-conifer communities. Through this framework, managers and stakeholders may better understand the contexts in which planting and passive recovery may better support ecological restoration.