Global trends in urban forest irrigation: Environmental influences, challenges and opportunities for sustainable practices across 109 cities worldwide
Urban forests are vital for climate resilience, yet irrigation practices remain poorly documented worldwide. Surveying 109 cities across 21 countries, this study provides one of the first global assessments of water sources, irrigation frequency, constraints and enabling conditions. Weather was the main driver of irrigation scheduling, while most cities lacked water‑use monitoring, recycled water, quality testing or financial incentives for efficiency. Only 15% used water‑efficient technologies, and nearly half had no plans for smart systems. Budget and infrastructure limitations were the most common barriers, with governance exerting stronger influence than environmental variables. Cities in the Global South reported distinct challenges and strategies. Findings offer actionable guidance for climate‑resilient urban water management and highlight the need for targeted policies, capacity‑building and efficient irrigation technologies.
Subject Tags
- Forest
- Climate impacts
Abstract
Urban forests are critical for climate adaptation and liveability, but effective irrigation management—key to their sustainability—remains poorly documented at the global scale. This study addresses this critical knowledge gap by analysing urban forest irrigation practices across 109 cities in 21 countries, offering one of the first global assessments of irrigation approaches, challenges and opportunities. Using survey data, we examined water sources, irrigation frequency, constraints and enabling conditions. Our results show that weather conditions were the leading factor influencing irrigation scheduling in 44% of cities, while 56% reported no formal water restrictions. Despite the importance of water conservation, 55% of respondents reported having no water usage monitoring systems, and 73% lacked financial incentives to promote water-efficient irrigation. A large majority (80%) did not use recycled wastewater, and 58% did not conduct water quality testing. Only 15% of cities regularly used water-efficient irrigation technologies, and 47% had no plans to implement smart systems. Over half (56%) rated their current irrigation practices as only moderately successful. Budget constraints and infrastructure limitations were the most frequently reported challenges, followed by climate change-related concerns. While environmental variables such as mean annual temperature and irrigation need influenced specific practices, local governance and institutional actions had stronger effects. Cities in the Global South reported distinct strategies and constraints compared to those in the Global North. Our findings provide actionable insights for climate-resilient urban water strategies and underscore the need for targeted policies, capacity-building and efficient technologies to enhance urban forest sustainability worldwide.
Citation
Esperon-Rodriguez, M., Gallagher, R. V., Russo, A., Power, S. A., Calaza-Martínez, P., Lourenço, T. C., ... & Tjoelker, M. G. (2025). Global trends in urban forest irrigation: Environmental influences, challenges and opportunities for sustainable practices across 109 cities worldwide. Sustainable cities and society, 130, 106510. https://doi.org/10.1016/j.scs.2025.106510
TNC Authors
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Robert I. McDonald
Lead Scientist for Nature-based Solutions, Europe
The Nature Conservancy
Email: rob_mcdonald@tnc.org