Urban Tree Health Monitoring at Grand-Scale: a Way to Target Unhealthy Individual Trees Using Remote Sensing

Green infrastructure is a key to sustainable development in urban environment. Trees in the parks and along the roadsides are part of green infrastructure and contribute to the health and wellbeing of the society. These trees should be monitored to identify problems at a broader scale and isolate those with health issues for detailed investigation.  Some of the health problems could be manifested in a form of discoloration and defoliation  [1].  Visual inspection is common practice to identify unhealthy trees but to observe in a grand scale, for example, county or city scale might be challenging. For this purpose, remote sensing data play an important role. We use hyperspectral images and Lidar observations to identify the changes and estimate the canopy density [2,3]. To understand the health status, we use images taken during the peak of the vegetation season where the leaves are not fallen off. The top-to-down approach will enable us to target individual trees and investigate further in detail at root and trunk levels. The overall approach will contribute the effort of the city councils to monitor trees and reduce the decision-making time in preserving them and the surrounding built environment. Keywords: Green infrastructure, tree health monitoring, hyperspectral images, Lidar   Acknowledgments: Sincere thanks to the following for their support: Lord Faringdon Charitable Trust, The Schroder Foundation, Cazenove Charitable Trust, Ernest Cook Trust, Sir Henry Keswick, Ian Bond, P. F. Charitable Trust, Prospect Investment Management Limited, The Adrian Swire Charitable Trust, The John Swire 1989 Charitable Trust, The Sackler Trust, The Tanlaw Foundation, and The Wyfold Charitable Trust. The Authors would also like to thank the Tree Service at the Ealing Council for facilitating this research.    References [1] Degerickx J, Roberts DA, McFadden JP, Hermy M, Somers B. Urban tree health assessment using airborne hyperspectral and LiDAR imagery. International Journal of Applied Earth Observation and Geoinformation 2018;73:26-38. [2] Hanssen F, Barton DN, Venter ZS, Nowell MS, Cimburova Z. Utilizing LiDAR data to map tree canopy for urban ecosystem extent and condition accounts in Oslo. Ecol Ind 2021;130:108007. [3] Tessema T, Uzor S, Mortimer D, Tosti F. Estimation of tree height using radar remote sensing in urban settings: a preliminary result. Proc. SPIE 12734, Earth Resources and Environmental Remote Sensing/GIS Applications XIV, 127340O (19 October 2023); https://doi.org/10.1117/12.2684325