All Reforestation Methods Can Support Tropical Tree Diversity Recovery, but Drivers and Species Composition Vary.

Area of Science:

• Ecology
• Conservation Biology
• Tropical Reforestation

Background:

• Tropical landscapes face rapid transformation impacting biodiversity and climate.
• Forest restoration is crucial for mitigating biodiversity loss and climate change.
• Standardized assessments of reforestation method effectiveness are lacking.

Purpose of the Study:

• To comprehensively compare tree diversity recovery across five reforestation methods.
• To identify drivers influencing biodiversity recovery in different restoration approaches.
• To evaluate the alignment of restoration strategies with local conditions for maximizing benefits.

Main Methods:

• Conducted tree inventories in 519 plots across rainforest and seasonally dry forests in Brazil.
• Compared five reforestation methods (natural regeneration, biodiverse plantings, monocultures, agroforests) against reference systems.
• Analyzed over 39,000 trees from 869 species to assess diversity and composition.

Main Results:

• Most reforestation methods, except short-rotation monocultures, supported tree diversity recovery.
• Naturally regenerating forests and restoration plantings approached degraded remnant diversity in rainforests.
• Biodiverse plantings and agroforests in seasonally dry forests matched conserved remnant diversity.
• Recovery drivers included forest age, climate, soil, and landscape context, varying by method.
• Naturally regenerating forests showed the highest species composition similarity to conserved remnants.

Conclusions:

• Reforestation outcomes vary significantly among and within methods.
• Naturally regenerating forests show strong potential for mimicking conserved forest composition.
• Restoration plantings and agroforests can achieve high diversity but may reduce overall species richness.
• Effective tropical forest restoration requires aligning methods with local environmental and landscape conditions.