Restoration interventions mediate tropical tree recruitment dynamics over time

Area of Science:

• Ecology
• Forestry
• Conservation Biology

Background:

• Forest restoration is vital for biodiversity conservation and climate change mitigation.
• Long-term comparative studies on forest restoration strategies and their impact on tree demographics are scarce.
• The UN Decade on Ecosystem Restoration emphasizes the need for science-based restoration approaches.

Purpose of the Study:

• To compare the long-term effects of natural regeneration, applied nucleation, and tree plantations on tree recruit survival and growth.
• To evaluate changes in tree recruit demographics over a decade across different restoration treatments.
• To assess the effectiveness of applied nucleation as a forest restoration strategy.

Main Methods:

• Annual measurement of tree recruit survival and growth over ten years.
• Comparison of three restoration treatments: natural regeneration, applied nucleation, and tree plantations.
• Replication of treatments across 13 forest sites in southern Costa Rica.

Main Results:

• Early-successional seedlings showed 14% higher survival in applied nucleation versus natural regeneration.
• Initial sapling growth rates were faster in natural regeneration and applied nucleation than plantations, but converged over time.
• Applied nucleation enhanced later-successional sapling growth by 39% compared to plantations.

Conclusions:

• Applied nucleation is as effective or more effective than resource-intensive tree plantations for enhancing tree recruit survival and growth.
• Tree recruit dynamics change rapidly, highlighting the necessity of multi-year studies for evaluating restoration interventions.
• Findings support applied nucleation as a promising strategy for effective forest landscape restoration.