Alberi e arbusti possono rendere le città più silenziose? Il ruolo delle foreste urbane nella mitigazione dell’inquinamento sonoro

Environmental noise pollution is widely recognized as a major source of environmental degradation worldwide, with road traffic representing the predominant contributor in urban areas. Exposure to sound levels above 55 dBA is associated with significant health risks, including sleep disturbances, psychosocial stress, and cardiovascular effects, as highlighted by the World Health Organization. Urban green spaces have emerged as an effective strategy for mitigating noise exposure, not only through physical sound attenuation mechanisms but also by providing psychological restoration that can reduce perceived noise annoyance. Dense vegetation barriers - particularly multilayered arrangements combining trees, shrubs, and ground cover - can provide considerable attenuation at medium and high frequencies. Species selection is therefore crucial and must consider climatic suitability, evergreen foliage, rapid growth, and planting density. However, the acoustic performance of vegetation is limited by physiological stressors typical of urban environments, including drought, heat, and pollution, which reduce plant vitality and thus their ecosystem service provision. ISO 9613-2 provides standardized methods for estimating attenuation due to foliage, showing modest but measurable reductions that increase with forest density and frequency. Overall, when properly designed, maintained, and integrated with site specific acoustic conditions, vegetation represents a multifunctional and ecologically valuable tool for mitigating urban noise and improving environmental and human well-being. Therefore, the purpose of this review is to evaluate the acoustic mitigation potential of urban forests, analyzing both the physical and psychological mechanisms involved, species-specific performance, and the operational limitations imposed by urban stressors and standard international predictive models.