UAV‐Based Precision Seed Dropping for Automated Reforestation

Wildfires and deforestation pose significant threats to forest ecosystems, motivating scalable methods for reforestation beyond labor-intensive cultivation of native forest seedlings in nurseries. To enable large-scale direct seeding of native species, this paper presents the design, analysis, and field evaluation of a UAV-based seed-dropping system. The approach integrates a lightweight carriage mechanism for gravity-based seeding systems with an open-source multirotor UAV to enable precision seeding operations. Precise seed placement enables adherence to ecologically motivated spacing, for example, 1.8 m for framework-species plots, which broadcast seeding cannot readily achieve. Additionally, the system uses 30 mm biochar-coated seed balls, which facilitate the handling of multiple seed varieties and enhance overall germination success in framework-species approaches. The autonomy stack combines LiDAR-based terrain following with deterministic actuation and on-board seed-drop confirmation via an outlet limit switch, providing a geotagged record of each seed drop for post hoc analysis of the reforestation efforts. Field evaluations at an active reforestation site in Northern Thailand have demonstrated the feasibility of the proposed solution. An altitude sensitivity study at 5, 10, and 15 m height revealed wind-aligned drift and terrain interactions; operations at 3–5 m height were found to provide practical operating windows for precision deployments, with 95% of drops landing within 0.66 m of the target for a controlled test at 5 m height. A representative 27-waypoint autonomous mission demonstrated a 90% success rate, with 24 drops confirmed by the on-board system and matched ground observations. Unlike conventional aerial seeding systems, the proposed precision seed-dropping approach significantly reduces seed wastage, making the solution scalable for large-scale ecological restoration and biodiversity recovery initiatives.