The impact of allergens emitted by urban green spaces on health is one of the main disservices of ecosystems. The objective of this work is to establish the potential allergenic value of some tree species in urban environments, so that the allergenicity of green spaces can be estimated through application of the Index of Urban Green Zones Allergenicity (I_UGZA). Multiple types of green spaces in Mediterranean cities were selected for the estimation of I_UGZ. The results show that some of the ornamental species native to the Mediterranean are among the main causative agents of allergy in the population; in particular, Oleaceae, Cupressaceae, Fagaceae, and Platanus hispanica. Variables of the strongest impact on I_UGZA were the bioclimatic characteristics of the territory and design aspects, such as the density of trees and the number of species. We concluded that the methodology to assess the allergenicity associated with urban trees and urban areas presented in this work opens new perspectives in the design and planning of urban green spaces, pointing out the need to consider the potential allergenicity of a species when selecting plant material to be used in cities. Only then can urban green areas be inclusive spaces, in terms of public health.

The urban heat island (UHI) is a critical issue in most urbanised areas. Spatial variation of urban air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and the energy demand for cooling. UHIs can be particularly harmful to human health and there are numerous studies that link mortality and morbidity with extreme thermal events, that can be worsened by UHIs. The temperature difference between city centres and the surrounding countryside, which is accentuated in the summer months and at night, is the result not only of a greater production of anthropogenic heat but is mainly due to the properties of urban surfaces. The use of vegetation, and in particular urban tree planting, is one of possible strategies to contrast the heat island effects. In order to analyse the mitigation effects produced by green spaces in the city of Padova, a municipality in the northeast of Italy, simulations of the air temperature variations and their spatial distribution were carried out using the i-Tree Cool Air model. High-resolution RGBir aerial photos were processed to produce a tree canopy and a permeability map and the model was applied on a 10 m × 10 m grid over the entire city, producing a raster map of the aboveground air temperatures. A particularly hot July day with recorded air temperatures of 35 °C at 3 p.m. and 28 °C at 10 p.m. at a reference weather station was chosen for the test. In the daytime, the results show temperature differences up to almost 10 °C between urban open spaces with impervious cover (squares, streets) and green areas under tree canopy. At night, the simulated air temperatures are only slightly cooler in areas with tree cover than those recorded at the reference station, while urban areas with sealed surfaces maintain air temperatures 4.4 °C higher. The study was aimed at testing the applicability of the model as a tool for predicting air temperatures in relation to land use and canopy cover. The results show that the model can potentially be used to compare different urban forest and urban greening planning scenarios, however, further research is necessary to assess the reliability of the temperature predictions.

Green spaces and trees are fundamental for the sustainability of cities. The use of management and planning indicators for green spaces, including urban forests, have been proposed, but are rarely applied and their potential to provide ecological, social, and economic benefits is usually overlooked by policy makers and managers. Here, we apply a set of indicators describing green spaces and their variability in different urban units within the Basso Isonzo, an area of the city of Padua (northern Italy). Eleven indicators were selected based on their capacity to consider availability, accessibility and the preservation or increase of urban green spaces and tree cover. The value of indicators was standardized and enabled to have five classes indicating increasing performance. The study indicates green spaces’ heterogeneous conditions. Interestingly, the indicators commonly change moving from the city center to the outskirts. Monitoring through these indicators will enable understanding whether specific management and planning targets are met and, in the absence of these targets, identifying main trends over time. The proposed approach and indicators applied are simple to collect, analyze, and convey information. The indicators are related to relevant social, economic and ecological conditions pertaining to green spaces. The proposed indicators can therefore be used as a simple tool to guide decision-making with the aim of enhancing green spaces.

Urban trees and green spaces provide a wide range of ecosystem services. Among urban green infrastructures, monumental trees represent key elements in these environments. Despite the growing recognition of their value, monumental trees in urban areas face multiple challenges, underscoring the need for targeted research to inform conservation and management strategies. This study investigates the ecological role of 124 urban monumental trees in the Veneto region (Italy) using tree-related microhabitats (TreMs) as a proxy for potential biodiversity support. Our analysis demonstrated that dendrometric characteristics (namely, diameter at breast height) and monumental tree configuration (namely, individual trees vs. those in groups) strongly affect the richness, abundance and composition of TreMs, highlighting that both native and non-native species contribute substantially to urban ecosystem functioning. Furthermore, complex relationships between monumentality criteria and TreMs were observed. These results are intended to support the management of urban green spaces, helping to enhance the biodiversity potential of monumental trees while preserving their multifaceted values.

Green spaces and trees are fundamental for the sustainability of cities. The use of management and planning indicators for green spaces, including urban forests, have been proposed, but are rarely applied and their potential to provide ecological, social, and economic benefits is usually overlooked by policy makers and managers. Here, we apply a set of indicators describing green spaces and their variability in different urban units within the Basso Isonzo, an area of the city of Padua (northern Italy). Eleven indicators were selected based on their capacity to consider availability, accessibility and the preservation or increase of urban green spaces and tree cover. The value of indicators was standardized and enabled to have five classes indicating increasing performance. The study indicates green spaces’ heterogeneous conditions. Interestingly, the indicators commonly change moving from the city center to the outskirts. Monitoring through these indicators will enable understanding whether specific management and planning targets are met and, in the absence of these targets, identifying main trends over time. The proposed approach and indicators applied are simple to collect, analyze, and convey information. The indicators are related to relevant social, economic and ecological conditions pertaining to green spaces. The proposed indicators can therefore be used as a simple tool to guide decision-making with the aim of enhancing green spaces.