Matching of forest restoration strategy to environmental conditions matters: evidence from south-central Ethiopia

Abstract

Introduction: Matching restoration strategies to environmental conditions is essential for successful forest landscape restoration in Ethiopia, but remains challenging due to limited guidance. Objectives: We evaluated the performance of restoration strategies based on forest stand structure and biomass across varying soil, elevation, and climate conditions. We hypothesized that (1) fertile sites with favorable climates enhance restoration success, and (2) tending operations improve performance in fertile areas. Methods: Using soil samples (0–10 cm) from 279 points in southern and central Ethiopia, and WorldClim climate data, we derived four environmental clusters through cluster analysis. We assessed forest structure attributes in plantations, woodlots (WL), boundary plantings (BP), and exclosures (EX) within these clusters. Results: Active restoration strategies achieved top heights comparable to natural forests, which had the highest aboveground biomass (AGB). BP (57.75 m2/ha) and WL (25.55 m2/ha) had higher basal areas than EX with the lowest top height (approximately 6 m) and biomass. Actively restored sites had better soil conditions than the passive. Clusters differed by elevation, soil fertility (fert-mid-high; orga-fert), and texture (clay-precip; sandy-low). Forest structure attributes were consistently higher in active than passive restoration strategies across clusters. Fertility-linked clusters had higher structural attributes across restoration strategies. Plantations in clayey, high-precipitation areas had the highest top height, AGB, and carbon storage. Clusters showed moderate correlation with mapped soil groups. Conclusions: Results show that soil fertility and precipitation strongly influence restoration success. Additionally, soil groups offer limited guidance for site suitability. Finally, BP offer an opportunity to meet household wood needs.