Climate-Change-Driven Droughts and Tree Mortality: Assessing the Potential of UAV-Derived Early Warning Metrics

• Published in: Remote sensing (Basel, Switzerland) Vol. 15; no. 10; p. 2627
• Main Authors: Ewane, Ewane Basil, Mohan, Midhun, Bajaj, Shaurya, Galgamuwa, G. A. Pabodha, Watt, Michael S., Arachchige, Pavithra Pitumpe, Hudak, Andrew T., Richardson, Gabriella, Ajithkumar, Nivedhitha, Srinivasan, Shruthi, Corte, Ana Paula Dalla, Johnson, Daniel J., Broadbent, Eben North, de-Miguel, Sergio, Bruscolini, Margherita, Young, Derek J. N., Shafai, Shahid, Abdullah, Meshal M., Jaafar, Wan Shafrina Wan Mohd, Doaemo, Willie, Silva, Carlos Alberto, Cardil, Adrian
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-05-2023
• Subjects: Artificial satellites in remote sensing; Biomass; biotic factors of tree mortality; Carbon; Carbon dioxide; Carbon sequestration; Carbon sinks; Climate adaptation; Climate change; Climate change mitigation; climate extremities; climate mitigation potential of forests; Climatic changes; Comparative analysis; Drone aircraft; drone remote sensing; Drought; drought-induced tree mortality; Droughts; Environmental aspects; Extreme drought; Forest fires; Forest management; Forests; Hydraulic equipment; Identification and classification; Measurement; Mortality; Optimization; Physiological effects; Physiology; Plant species; Remote sensing; Resource allocation; Stress (physiology); Trees; United States; Unmanned aerial vehicles; Vegetation; United States
• ISSN: 2072-4292; 2072-4292
• DOI: 10.3390/rs15102627

Protecting and enhancing forest carbon sinks is considered a natural solution for mitigating climate change. However, the increasing frequency, intensity, and duration of droughts due to climate change can threaten the stability and growth of existing forest carbon sinks. Extreme droughts weaken plant hydraulic systems, can lead to tree mortality events, and may reduce forest diversity, making forests more vulnerable to subsequent forest disturbances, such as forest fires or pest infestations. Although early warning metrics (EWMs) derived using satellite remote sensing data are now being tested for predicting post-drought plant physiological stress and mortality, applications of unmanned aerial vehicles (UAVs) are yet to be explored extensively. Herein, we provide twenty-four prospective approaches classified into five categories: (i) physiological complexities, (ii) site-specific and confounding (abiotic) factors, (iii) interactions with biotic agents, (iv) forest carbon monitoring and optimization, and (v) technological and infrastructural developments, for adoption, future operationalization, and upscaling of UAV-based frameworks for EWM applications. These UAV considerations are paramount as they hold the potential to bridge the gap between field inventory and satellite remote sensing for assessing forest characteristics and their responses to drought conditions, identifying and prioritizing conservation needs of vulnerable and/or high-carbon-efficient tree species for efficient allocation of resources, and optimizing forest carbon management with climate change adaptation and mitigation practices in a timely and cost-effective manner.