Use of drones for the detection of Ailanthus altissima in the USA
Ailanthus altissima (Simaroubaceae - EPPO List of Invasive Alien Plants) commonly known as the tree of heaven is an invasive alien plant species in the EPPO region and native to Asia. It can invade a variety of habitats including managed and unmanaged grasslands, forests, riverbanks/canal-sides, rail/roadsides, wasteland, and urban areas. It is also an invasive species in the USA and a preferred host of an invasive insect, the spotted lanternfly (Lycorma delicatula: Hemiptera: Fulgoridae: EPPO A1 List of pests recommended for regulation). In the USA, managers of the species rely on ground surveys for detecting both A. altissima and L. delicatula. The use of drones equipped with optical sensors were used to explore their efficacy in detecting A. altissima. Aerial surveys were conducted to determine the optimal season, sensor type, and flight altitudes for A. altissima detection. The results revealed that A. altissima can be detected at different times of the year and at specific flight heights. Male inflorescences were identifiable using an RGB (red, green, blue) sensor in the spring at <40 m, seed clusters were identifiable in summer and autumn at <25 m using an RGB sensor, and remnant seed clusters were identifiable in the winter at <20 m using RGB and thermal sensors. In combination, throughout the year, it is possible to detect both male and female A. altissima using drone technology. Drone technology, with optical sensors can provide an efficient method to aid in the development of effective strategies for monitoring managing A. altissima and monitoring L. delicatula.
Sources
Naharki K, Huebner CD, Park YL (2024) The detection of tree of heaven (Ailanthus altissima) using drones and optical sensors: implications for the management of invasive plants and insects. Drones 8, 1. https://doi.org/10.3390/drones8010001