Beyond Urban Forests: The Multiple Functions and the Overlooked Role of Semi-Natural Ecosystems in Mediterranean Cities

In recent times, the misleading belief that the indiscriminate planting of a million trees is the panacea to some of the most serious and urgent environmental problems of our planet (such as soil erosion, climate change, etc.) has gained increasing popularity. However, the idea of “reforesting the planet” does not seem to adequately consider the fact that forests most often represent the last successional stage of terrestrial ecosystems, thus requiring—at least in the first years after planting within urban contexts—some care (hence time and money resources) to become large enough to fulfil the functions (climate mitigation, particulate capture, air purification, etc.) expected by public opinion. Starting from these critical considerations, this paper aims to highlight the need to carry out in-depth multidisciplinary investigations on the most suitable species and communities, underlining the fact that, to improve the environmental quality in urban areas, it is necessary to make appropriate choices, also considering the biogeographical contexts in which such interventions are made.