Research on the mechanisms of urban plant landscapes on older adults’ physical and mental health and age-friendly design responses

Urbanization and population ageing form a compounding risk: the urban heat island effect intensifies thermal and air-pollution stress where the residents least able to thermoregulate are concentrated, with epidemiological evidence confirming disproportionate heat-related morbidity and mortality among adults aged 65 and over. Plant landscapes offer a principal nature-based means of moderating this burden, yet existing reviews address vegetation cooling and the psychological effects of green space separately; few are age-specific, and fewer still translate evidence into design guidance. This review integrates physiological and psychological pathways into a single mechanism chain — “environmental comfort → behavioural participation → psychological restoration” — and translates that chain into hierarchical criteria for age-friendly planting design. Drawing on 221 Chinese-language and 379 English-language articles (2000–2024) from the Chinese Science and Technology Journal Database and the Web of Science Core Collection, we combined CiteSpace bibliometric mapping with structured content analysis. Key findings include: a 10% increase in green space area lowers ambient temperature by 0.2–0.9 °C, trees achieve a mean cooling of 2.8 °C, and tree belts ≥ 40 m wide reduce PM2.5 by up to 67%; psychologically, an interquartile-range increase in residential greenness (NDVI) is associated with approximately 5% lower non-Alzheimer’s dementia risk. Research remains concentrated on parks used by healthy, ambulant older adults, whereas the oldest-old, functionally impaired residents and long-term care settings are markedly under-represented. We argue for a shift from universal to compensatory precision design, repositioning planting from backdrop to active health intervention.