Productivity, work quality and tree performance of a mechanised planting machine in Eswatini

Abstract

Manual planting methods remain the primary way of regenerating forest stands in southern Africa, but mechanised planting machines are attracting increasing interest due to their reduced labour requirements, better ergonomics and safety. This study analyses the performance of the first fully mechanised planter deployed in the region and offers information on the productivity, work quality and tree performance (survival and growth at 3, 6, 9 and 12 months) achieved with a single-head excavator-based planting machine in Eswatini. The machine was run alternately by two operators and tested on 17 plots distributed across two study sites while planting Eucalyptus smithii seedlings at 1 667 stems ha⁻¹. Time and motion studies were used to gather and analyse productivity (plants planted per productive machine hour (PMH)), followed by post-planting assessments to rate mechanised work quality. Productivity averaged 165 plants PMH⁻¹, excluding delays. Mechanical availability was 71% and machine utilisation was 56%. Machine productivity was higher on the site with a low residue load. Operator 1 achieved 30% higher productivity than Operator 2 on the site with a higher residue load. The mechanised planting cost was US$1 015 ha⁻¹. Half of the seedlings were planted correctly. Initial tree survival was lower than that of manually planted trees, but differences evened out after 12 months. Tree growth was higher on the site with a higher residue load. The study serves as a baseline for future mechanised planting performance assessments in the southern African region.