Enrichment planting in tropical and subtropical forest restoration: patterns, practices, and knowledge gaps

Introduction In ecosystem restoration, enrichment planting (EP) seeks to increase the density of desired species that cannot reestablish naturally. However, a comprehensive knowledge of how EP has been adopted and implemented in practice, particularly for restoration purposes, is lacking. Objectives We synthesize global patterns and practices of EP activities and identify key knowledge gaps related to monitoring approaches, ecological outcomes, and drivers of success. Methods We surveyed 74 papers (768 data points) implementing EP activities to restore tropical and subtropical forests in 67 locations across 14 countries. We specifically (1) described the most common techniques and species used, (2) identified outcome variables, and (3) identified factors driving those outcomes. Results EP is primarily used in the Neotropics; there, with a focus more on fostering natural regeneration than improving actively planted stands. Non‐pioneer native trees, including wind and animal‐dispersed species, are mainly introduced as seedlings or saplings. Studies mostly monitor only the survival and growth of introduced species (79%), rarely evaluating diversity (12%) or functions (14%). Monitoring time is usually short‐term (≤5 years, ≥70% of the studies). Conclusions EP has been applied primarily as a context‐specific intervention within naturally regenerating forests, evaluated through a narrow set of indicators and over short time frames, yet its effectiveness appears to depend on strategic implementation.