International Journal of Environment and Climate Change

Urban forestry is increasingly positioned as essential infrastructure for climate adaptation, public health, biodiversity conservation and liveability. Yet the evidence base is often translated into simple canopy-expansion targets that obscure variation in ecological function, spatial context, maintenance burden and social distribution. This critical narrative review evaluates how urban trees and wooded systems generate ecosystem services, where benefits are conditional, which trade-offs and disservices can arise, and how management can secure long-term and equitable outcomes. Peer-reviewed literature published from 2000 to 1 June 2026 was identified through multidisciplinary scholarly indexes, citation searching and verified article records, with earlier foundational evidence eligible when necessary. Evidence was appraised for design quality, spatial and temporal scale, measurement validity, treatment of confounding, geographical transferability and relevance to management. The synthesis indicates strongest and most consistent support for local shade and heat-exposure reduction, stormwater interception and infiltration under suitable soil conditions, habitat provision, and multiple pathways linking accessible green environments with health and wellbeing. Evidence for city-wide air-quality improvement, climate mitigation through carbon sequestration, and universal health effects is more conditional because outcomes depend on urban form, species traits, background climate, exposure definition, maintenance and population context. Tree planting can also create or intensify problems, including restricted street-canyon ventilation, allergenic pollen, water demand, infrastructure conflicts, branch or whole-tree risk, invasive potential, inequitable benefit distribution and green-led displacement. These effects are neither arguments against urban forestry nor minor externalities; they demonstrate that benefits emerge from a managed social–ecological system rather than from tree numbers alone. Effective practice therefore requires service-specific objectives, climate-ready and functionally diverse species portfolios, adequate rooting environments, establishment care, lifecycle budgeting, risk management, participatory governance, equity safeguards and repeated performance monitoring. The central conclusion is that sustainable urban forestry should be judged by durable, context-appropriate and fairly distributed service delivery, not merely by planting totals or aggregate canopy cover.