LIFE-CLIVUT, ecosystem benefits of urban green areas: a pilot case study in Perugia (Italy)

Trees have a great value in terms of ecosystem services in urban areas. LIFE CLIVUT is an “Information and Governance” European project developed in 4 Mediterranean Cities, with the goal of increasing the knowledge and awareness of citizens, especially young people, on the importance of the presence and good management of urban trees to mitigate the “Heat Island” effects. The data collected on the value of tree heritage and their future potential are used to design a green asset management strategy that will help urban planners adopt better practices for the mitigation of the effects of climate change in urban environments. This paper illustrates the results of tree census activity in four urban green areas of Perugia, Central Italy, that will be compared with those recorded in others cities involved in the project. Dendrometric parameters (diameter at breast height, tree height, first branch height, max and min crown width, crown shape and density) were recorded in situ using a dedicated software operating through a web app (“Clivut-Treedb”). The following ecosystem services were estimated: CO2 sequestration, particulate matter (PM) absorption, shadow effect, biodiversity indexes. Several tree species characterized by important wood structures during their adult phase, such as Pinus pinea, Quercus ilex, Q. pubescens, Ulmus carpinifolia, Populus alba and Aesculus hippocastanum showed the highest estimates of CO2 stored. Q. ilex was the most efficient species in particulate adsorption, showing similar estimates (about 60 g PM10 tree-1 year-1) in the 3 oldest green areas established in the 1980s, while the youngest plantations (dating back to 2005) absorbed about 10 g tree-1 of PM10 per year. In terms of the potential cooling effect of trees, preliminary estimates of the shaded areas highlighted the difference between the older green areas (about 50% of shading) compared to the younger ones (about 15% and 8%).