Monitoring Recent Afforestation Interventions as Relevant Issue for Urban Planning

In the UN Decade on restoration, urban and peri-urban areas are increasingly recognized as key to implement afforestation interventions, thus contributing to supporting ecosystem services provision. Nevertheless, the relation between the current vegetation health and typologies of Land Use/Land Cover (LULC) and related changes is still poorly explored, thus affecting ecosystem planning. Therefore, this study aims to investigate, through the employment of Normalized Difference Vegetation Index (NDVI), the vegetations’ health in i) unchanged forest ii) afforested areas - considering the different LULC classes in which afforestation occurred iii) unchanged LULC classes in the surrounding of afforested areas; in the case study area of the Metropolitan City of Milan. We first analyze the LULC transformation aimed at identifying unchanged forest (1954–2018), recent afforested areas (2012–2018), and the unchanged LULC surrounding the afforested areas (2012–2018) i.e., being the same LULC that preceded the afforestation process. We then analyzed Sentinel-2 NDVI sequences (2017–2023) in these three LULC transformation/unchanged categories, respectively. The results show lower NDVI values in afforested areas transformed from impervious soil and arable lands into forest. Moreover, the results of the Wilcoxon test indicate that the average NDVI values of recently afforested areas from impervious soil, arable lands and pastures are statistically different from those of unchanged forest. Results can be used to set an environmental benchmark for afforestation processes providing a basis in the selection of future planning priorities.