Environmental equity and urban afforestation in the extreme northeastern Brazilian Amazon

Urban areas with low tree cover in Brazil are found mainly in the Amazon, highlighting the disparities in access to benefits of urban greening. The goal of this study was to analyze how urban afforestation is associated with sociodemographic factors to understand the distribution of trees (and their benefits) among different social segments in the city of Macapá, in the extreme Northeastern Amazon. We conducted a floristic inventory in 217 blocks belonging to 32 neighborhoods, and classified species according to origin (exotic or native) and fruit use (fruit-bearing or non-fruit-bearing). Additionally, we selected 12 variables to represent sociodemographic gradients among neighborhoods. We reduced the dimensionality of floristic and sociodemographic data using ordination techniques, and used their first axes to represent gradients of species composition and sociodemographic factors. The effect of sociodemographic gradients on tree abundance, species richness and composition was tested using generalized linear models. The results indicate that most urban trees are exotic, non-fruit-bearing, and of medium size (10–30 cm in diameter). Older neighborhoods with higher human population age and income showed higher tree abundance and higher species richness. The species composition was related to the gradient of human population density, proportion of old people, income, and household occupancy. Large non-fruit trees were more frequent in neighborhoods with low population density. Exotic trees were more frequent in older neighborhoods with older people and high income, and large fruit trees showed higher abundance in neighborhoods with low household occupancy rates. Ensuring that low-income neighborhoods and historically marginalized communities have equal access to green spaces and adequate tree coverage is a key element to promote environmental justice and to develop healthier and more sustainable cities.