Continuous cover forestry for carbon sequestration: Opportunities, challenges and future directions

Continuous cover forestry (CCF) has been widely proposed to increase carbon sequestration in forest ecosystems for mitigating global climate change. To this end, many experimental studies have examined carbon dynamics following CCF management. However, no comprehensive review has synthesized its overall potential to enhance carbon sequestration across forest carbon pools. Building on relevant theories and empirical research, this global synthesis presents a comprehensive understanding of how thinning and selective harvesting as common CCF management tools along with mixed-species composition and high structural diversity as common CCF features, can promote carbon sequestration in aboveground and belowground tree biomass, understorey vegetation, and soil. Existing research shows that thinning and selective harvesting at reasonable intensity can promote carbon sequestration in these vital carbon pools. Moreover, mixed-species and structurally diverse forests can increase carbon sequestration in tree biomass and soil, while reducing carbon losses associated with biotic disturbances. Understanding how intervention intensity, recovery time, and species composition affect various carbon pools is crucial to maximising carbon sequestration under CCF. High-intensity interventions, particularly in older tree cohorts, should be avoided, as carbon sequestration only slowly recovers after such interventions. Soil carbon responses require long-term observation before robust conclusions can be drawn. Overall, we conclude that CCF can effectively promote carbon sequestration in most forest ecosystems, and thus can play an essential role in mitigating climate change. However, uncertainties remain due to limited long-term experiments simultaneously monitoring multiple carbon pools. Such data are needed to better understand the carbon sequestration potential of forest ecosystems under CCF. • A global synthesis presenting the potentials of CCF for carbon sequestration. • CCF promotes carbon sequestration in tree biomass, understorey vegetation and soil. • High-intensity intervention should be avoided to enhance carbon sequestration. • Making robust conclusions on soil carbon sequestration needs long-term observation. • CCF can play a role in mitigating climate change through increasing sequestration.