Abstract Urban greening is increasingly promoted within European and international regulations as ‘Nature-Based Solutions’ (NBS) concept, to enhance biodiversity and mitigate the urban heat island (UHI) effect. Within the LIFE CityAdap3 project, the city of Reggio Emilia (Italy) implemented “Climate-Friendly Parks” interventions across public green areas. This study focuses on one of these green areas, Marco Biagi Park, where multiple NBS were established between 2021 and 2022, including two Miyawaki microforests —a Native Forest (NF) and an Adaptive Forest (AF) —, a wetland system, rural hedgerows and trees rows. An environmental monitoring program was conducted to evaluate: (i) growth performance and structural development of the two microforests through mortality rate, relative growth rates (RGR H and RGR DBH ) and slenderness ratio (SR); (ii) floristic dynamics and ecological composition of the wetland area; and (iii) microclimatic regulation across different NBS sites and surrounding built-up areas. Linear mixed-effects models were applied to detect spatial and interannual patterns. Three years after planting, both microforests showed very low mortality and comparable overall growth, confirming successful establishment. However, differences in growth allocation emerged: AF species invested relatively more in diameter growth and structural stability, while NF species displayed greater variability and more height-oriented development. Both forests exhibited a decline in SR over time, a typical adjustment under high-density conditions. The wetland showed a rapid floristic enrichment (+ 69% species richness in one year), with early functional zonation and an increase in Mediterranean chorotypes, suggesting a dynamic community assembly in response to urban environmental conditions. Microclimatic results showed consistently cooler and more humid conditions within microforests compared to built-up areas, while differences between NF and AF were limited and influenced by interannual variability. Overall, the findings highlight and quantify the capacity of integrated blue–green infrastructures to enhance biodiversity, support rapid vegetation development and mitigate urban heat, supporting the combined use of native and climate-adaptive species in future urban afforestation strategies.
Santunione et al. (Mon,) studied this question.