Abstract
Unoccupied Aircraft Systems (UAS) are beginning to replace conventional forest plot mensuration through their use as low-cost and powerful remote sensing tools for monitoring growth, estimating biomass, evaluating carbon stocks and detecting weeds; however, physical samples remain mostly collected through time-consuming, expensive and potentially dangerous conventional techniques. Such conventional techniques include the use of arborists to climb the trees to retrieve samples, shooting branches with firearms from the ground, canopy cranes or the use of pole-mounted saws to access lower branches. UAS hold much potential to improve the safety, efficiency, and reduce the cost of acquiring canopy samples. In this work, we describe and demonstrate four iterations of 3D printed canopy sampling UAS. This work includes detailed explanations of designs and how each iteration informed the design decisions in the subsequent iteration. The fourth iteration of the aircraft was tested for the collection of 30 canopy samples from three tree species: eucalyptus pulchella, eucalyptus globulus and acacia dealbata trees. The collection times ranged from 1 min and 23 s, up to 3 min and 41 s for more distant and challenging to capture samples. A vision for the next iteration of this design is also provided. Future work may explore the integration of advanced remote sensing techniques with UAS-based canopy sampling to progress towards a fully-automated and holistic forest information capture system.
Highlights
Climate change is having a complex variety of effects on our forests from increased atmospheric carbon dioxide levels [1,2], environmental changes such as increasing drought severity and frequency [3,4,5], and more frequent and severe bushfires [6]
By using Visual Inertial Odometry (VIO) and Robotic Operating System (ROS) to provide position control of our aircraft, it was possible to facilitate precise cutting movements with the aircraft, while the simple collision shield reduced the risk of branch-propeller interactions and prevented the aircraft from flying too deeply into the canopy
Precision flight capabilities are not critical for this application, as the hedge trimmer sample collection approach is relatively simple for an adequately skilled pilot to perform in calm conditions; VIO based position control makes this operation considerably safer, simpler, and more precise, especially at greater distances from the pilot
Summary
Climate change is having a complex variety of effects on our forests from increased atmospheric carbon dioxide levels [1,2], environmental changes such as increasing drought severity and frequency [3,4,5], and more frequent and severe bushfires [6]. Local environmental changes are becoming sufficiently persistent and significant enough to shift conditions beyond the tolerable limits of some species, causing the large scale loss of forests and even threatening some species with extinction without assisted migration [7,8]. Scalable and high-fidelity measurements are of considerable importance to furthering our understanding of these changing conditions and their associated impacts on our forests. Forest information will play an important role in enabling evidence-based policy decisions to be made regarding the mitigation of and adaptation to such climate impacts. Unoccupied Aircraft Systems (UAS), remote-sensing and deep-learning technologies have been revolutionising the way we can monitor the structure of forests and quantify carbon stores [9,10,11,12,13,14,15,16,17,18] for use in climate models; physical samples remain important for calibrating some remote sensing techniques [19,20], directly measuring foliar nutrients, collecting genetic samples, monitoring pests/diseases and studying physical plant traits
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
