TIPWG Drone webinar: Silvicultural and research application

On 12 November 2025, the Timber Industry Pesticide Working Group (TIPWG), under Forestry South Africa (FSA), hosted an online Drone Workshop showcasing the latest innovations shaping silviculture and forestry research. The workshop highlighted how drone technology is transforming forest management, from precision pesticide application to advanced, data-driven environmental monitoring. Through these presentations, attendees gained valuable insights into how Unmanned Aerial Vehicles (UAVs) are improving sustainability, enhancing operational accuracy, and strengthening research capacity across the forestry sector. A summary of the presentations is provided below.

Professor Ilaria Germishuizen from ICFR presented on “Unmanned Aerial Systems for Enhanced Forestry Research: Insights from ICFR”. Her presentation began with an overview of how unmanned aerial vehicles (UAVs) are increasingly vital tools in forestry research, providing high-resolution, repeatable data that bridge the gap between satellite imagery and traditional ground surveys. She then discussed their ability to operate at various spatial and temporal scales, enabling more efficient monitoring of forest productivity, seasonal changes, and overall stand health. Hereafter, she described how various sensors can be mounted on drones, including RGB cameras for basic imagery, multispectral sensors for assessing chlorophyll levels and stress, hyperspectral sensors for detailed chemical information, and LiDAR for capturing three-dimensional forest structure. The choice of sensor depends on the research goal, required resolution, payload limitations, flight duration, and the substantial data-processing demands of these technologies. Due to these challenges, ICFR, FABI, Stellenbosch University, and partner institutions established a collaborative remote-sensing platform to standardise data collection, develop spectral libraries, and build technical capacity. This collaboration supports projects such as using multispectral drone imagery to distinguish Eucalyptus hybrid clones across seasons with high accuracy. She concluded by emphasising that drones significantly enhance precision forestry and successful implementation requires careful planning, strong data management, and coordinated institutional effort.

Professor Dave Drew from the University of Stellenbosch presented on “Linking remote sensing with growth truth at the IMPACT OAL and beyond”. The presentation outlined the work being done at the IMPACT Open Air Laboratory, a 10-hectare experimental site designed to study how four contrasting Eucalyptus species (cladocalyx, grandis, pellita, and urophylla) respond to different spacing treatments while generating ultra-high-resolution datasets for advanced forest-growth modelling. Initial testing of satellite imagery, such as WorldView, Sentinel-2, and Wyvern hyperspectral data, showed that even with 5 m pixels and multiple spectral bands, products cannot see individual trees. This led researchers to rely on airborne hyperspectral sensors, LiDAR drones, DJI multispectral drones, and an autonomous DJI Dock 2 system capable of weekly flights with pixel sizes as small as 2-6 mm. These tools allow detailed monitoring of canopy development, leaf loss, stress indicators, and plot-level variation. Several student projects support calibration and ground-truthing using remote sensing

• They can measure leaf-level gas exchange and physiological responses, showing clear differences among species and spacing,

• Develop NDVI calibration curves under controlled drought to link leaf-level spectral responses to drone imagery,

• Automate the extraction of canopy height and structure from weekly drone flights,

• Use terrestrial LiDAR to build 3D crown models and extract leaf-angle and density metrics,

• Show how Eucalyptus trees rapidly increase physiological activity following short rainfall pulses.

Additionally, continuous monitoring is provided through low-cost LoRa-based loggers, which record hourly soil and climatic variables as well as stem growth via dendrometers. Together, these high-resolution datasets are fed into an AI-driven modelling framework, supported by the Information Hub and Stellenbosch University’s data-science teams, enabling improved prediction of growth, stress responses, and management outcomes while supporting collaborative research across the forestry sector.

Dr Sam van Holsbeeck from the University of the Sunshine Coast presented on “Spray smarter: Opportunities and challenges of drone-based pesticide application in Australian plantations”. The presentation examined the rapid growth of drone-based pesticide application in Australian forestry, highlighting its cost competitiveness, precision, and operational speed compared with helicopters and ground-based systems. Despite regulatory and technical challenges, drones are now used across thousands of hectares each year, supported by an expanding contractor network and strong industry uptake. Research led through the Forest Pest Management Research Consortium focuses on understanding spray drift so forestry can maintain access to essential pesticides. Earlier national regulations (APVMA, 2008) often produced overly large buffer zones, sometimes 400-800 m, which restricted chemical use. However, studies using drift-reduction technologies, particularly active-flow nozzles on helicopters, showed significant improvements, reducing buffers to as little as 25 m, making aerial application operationally feasible again. To refine drift modelling, researchers use wind-tunnel experiments to measure droplet size distributions (DSDs) and feed this data into the AgDRIFT/AGDISP modelling system, which simulates deposition curves and predicts buffer requirements. Because drones cannot be tested in wind tunnels the same way helicopters can, due to downward-facing and centrifugal nozzles, researchers conducted field studies with DJI T10 and T30 drones, finding that spray deposition generally fell within 16 m and that lowering the release height reduced drift. Additional tunnel tests using drone nozzles helped adapt helicopter-based models, though drone turbulence patterns remain poorly represented. Ongoing PhD research is comparing 4,6, and 8-rotor drones to helicopters across different flight heights, speeds, canopy densities, and tank additives (“adjuvants”), as early results show inconsistent and sometimes counterintuitive chemical behaviours. The long-term aim is to improve regulatory modelling for drones, develop dedicated drift-prediction tools, and advance future capabilities such as vision-based weed detection and targeted spot spraying, which would greatly reduce chemical use and increase operational efficiency.

Mr Greg Fuller from ICFR presented on “The long road to becoming a legally compliant drone unit in South Africa – The ICFR journey. His presentation described the extensive 11-month journey taken to establish a legally compliant drone research unit in South Africa, beginning in August 2023 with the arrival of a DJI Matrice 350 RTK drone and a high-specification American-made camera system. Although the equipment was advanced, the team realised that legal operation required multiple licences and approvals under the South African Civil Aviation Authority, including Remote Pilot Licences (RPLs), Letters of Approval, drone registration, maintenance oversight, landowner permissions, insurance, and medical certification. Pilots underwent intensive training through Drone Legal Safety, completing aviation-level theory on air law, meteorology, navigation, human factors, and radio telephony, followed by practical flying and examinations with SACAA-designated examiners. Technical challenges, such as integrating foreign-made camera systems, were resolved, but the team remained unable to operate independently because they lacked an expensive and resource-heavy ROC (Remote Operator Certificate), a requirement affecting many research institutions. After lobbying attempts failed, they joined an existing ROC, completing additional aviation security training and aircraft approvals. Even once qualified, every flight required complex planning, including NOTAM checks, flight polygons, risk assessments, weather analysis, pre- and post-flight documentation, and radio calls to nearby air traffic. The unit finally achieved full compliance on 31 July 2024 and completed its first legal solo flight, despite an encounter with territorial long-crested eagles. Since then, the team has completed 166 flights, captured hundreds of thousands of images, and surveyed thousands of hectares of forestry land, marking a significant milestone in building a fully legal and operational drone capability for forestry research.

Mr Jaco Nel from DC Geomatics presented on “UAV- Operations and standards”. He began his presentation by highlighting the value of industry involvement in discussions about drone use in South African forestry. He referenced earlier presentations that examined key studies on legal requirements, compliance challenges, and operational risks associated with drone deployment. These studies aimed to understand how regulatory restrictions such as licensing, pilot competency, airspace rules, and operational limitations affect the safe and efficient use of drones in commercial environments. The findings consistently showed that compliance with Part 101 of the South African Civil Aviation Regulations is not only a legal obligation but also essential for ensuring flight safety, continuity of operations, and organisational protection against liability. Using these insights, he introduced DC Dramatics, a drone technology company established in 2015 and operating under the updated UASOC regulations. With over 105 licensed pilots, 133 registered drones, and more than 80,000 audited safe flights, the company serves as a practical example of how the regulatory framework can be implemented effectively. He indicated that research demonstrated that obtaining and maintaining an ROC (now UASOC) is expensive, time-consuming, and requires at least five specialised full-time positions, making independent compliance challenging for most organisations. Furthermore, results from compliance-focused studies show that outsourcing flight operations to an approved operator significantly reduces cost, administrative load, and legal exposure. Applying these findings, he explained that DC Dramatics provides a solution by allowing trained pilots and organisations to operate legally under their UASOC. They manage all regulatory requirements, including flight approvals, logbooks, BVLOS operations, night operations, and safety oversight, ensuring that clients can use drones effectively without needing to build an internal aviation department. Finally, he indicated that drone operations in South Africa require strict adherence to aviation standards, and partnering with an established UASOC holder is a practical, cost-effective way to achieve safe, compliant, and scalable drone use in forestry and other sectors.