Drone-Based Vegetation Management for Forestry Operations

Note: The AI-generated image is for illustrative purposes only and does not depict a real UAV system or a vegetation management system that has actually been developed or is ready for use. The image is not representative of existing technical solutions or specific use cases.

Clearing vegetation around young trees is one of the most labour-intensive and costly tasks in Austrian forestry. Dense weeds block sunlight, slow growth and make it difficult to assess frost damage. Because the terrain is often steep and difficult to access, this work is still done manually with hand tools. It costs around 1,000 euros per hectare, takes 20 seconds per tree—and must be repeated up to three times a year on hundreds of hectares. The shortage of skilled workers makes the problem even more pressing.

This was the starting point for a feasibility study conducted as part of an internship at AIRlabs Austria, together with FH JOANNEUM and the forestry partner Forstbetrieb Franz Mayr-Melnhof-Saurau. The question was simple yet ambitious: Can a drone do this job faster, safer and more efficiently than a human?

The idea was to develop a multirotor UAV equipped with a cutting tool that flies at low altitude, detects weeds and removes them without damaging young trees. Interviews with Forstbetrieb Franz Mayr-Melnhof-Saurau confirmed the relevance of such a system and defined critical requirements: the drone must navigate between trees spaced 2–3 metres apart, avoid trunks just 1–2 cm thick and handle vegetation with leaves up to 40 cm high. Precision matters: one wrong cut can damage an entire generation of young trees.

Technical analysis showed that a cutting-wire system is the most suitable method. Laser- or chemical-based approaches turned out to be less practical or riskier. A platform such as the DJI Matrice 300 RTK could theoretically supply enough energy for flight and cutting operations, provided the cutting tool runs intermittently. Integration would require a power converter, low-altitude stability control and a protective shield around the cutting head to prevent debris from hitting the propellers.

From a regulatory perspective, the system would likely fall under the Specific category. In correspondence with Austro Control, the authority clarified that not only the drone dimensions but also the rotating blade must be considered for classification. A check of the ICAO Dangerous Goods categories (ICAO Doc 9284) confirmed that the cutting tool is not classified as dangerous goods.

Using the SORA methodology, the feasibility study determined an intrinsic Ground Risk Class of 2 and an Air Risk Class of ARC-a, resulting in SAIL 1. This keeps operational requirements manageable, but still necessitates an emergency plan covering power loss, blade failure, unexpected presence of people or animals, and loss of control link.

Forestry companies are actively looking for solutions that reduce manual labour, prevent tree loss and increase efficiency. Although there are currently no aerial brush-cutting systems on the market, public support for drones in Agriculture, Nature Protection and Surveying is already high. This creates favourable conditions for a technology that lowers environmental impact, avoids soil compaction and mitigates risks for workers.