Socio-spatial patterns of environmental justice in Mediterranean cities. An approach based on urban tree cover density in four case studies

Abstract

Environmental justice has been widely investigated in North American and Northern European contexts, but there are few comparative analyses of Mediterranean cities and these are methodologically fragmented. This study focuses on Barcelona, Valencia, Palermo and Catania, and investigates whether Mediterranean cities share common socio-spatial regimes in the distribution of urban tree cover density. It also explores how these regimes are associated with housing-market conditions, educational attainment, population ageing and the spatial concentration of foreign residents. To overcome differences in administrative geographies and data structures, environmental and socio-demographic information is integrated into a harmonized 100 × 100m grid. A Finite Mixture of Beta Regression (FMBR) is then used to identify latent intra-urban regimes in which the relationship between tree cover density and socio-demographic variables remains internally homogeneous. The results show that Mediterranean urban greening is not organized through a single social gradient. Barcelona appears highly segmented, Valencia is dominated by a broad low-greenness regime interrupted by small greener enclaves, Palermo combines an extensive low-greenness fabric with smaller green pockets, and Catania is more socially differentiated than environmentally polarized. Housing-market pressure, the concentration of the foreign population, household structure, education and ageing are important factors, but vary in significance across the regimes. This paper confirms that the four cities feature constrained greening, with variations according to local morphology, land-market pressure and demographic composition. These findings support urban greening policies that are sensitive not only to aggregate canopy deficits, but also to the socio-spatial regimes through which environmental amenities are unevenly distributed.