Evaluation of the adaptability and response of indigenous trees to assisted rehabilitation on the degraded hillsides of Kuriftu Lake Catchment (Debre Zeit, Ethiopia)

Abstract

Removal of trees and shrubs from hillsides exposes a site to erosion that threatens soil aggregation and stability. The present study aimed at evaluating the performance of five indigenous tree species in rehabilitation of degraded hillsides of Kuriftu Lake Catchment and the role of water harvesting structures. Adaptability varied by tree species and water harvesting structures significantly augmented seedling establishment for some tree species. Height of Acacia abyssinica planted on steeper slopes (18%–27%) without infiltration pits was lower than for conspecifics planted with infiltration pits. Dodonaea angustifolia was proved to be best adapted to the site and showed no need for water harvesting regardless of planting position across the degraded hillside. Planting of Acacia seyal should be restricted to gentler slopes (0–17%) with infiltration pits: tree height declined significantly on steep slopes without infiltration pits. Olea africana performed better on gentle slopes with pits but also grew well on steeper slopes with pits. Euclea schimperi was proved to be least effective of the species evaluated in this study.