Urban tree cover has important environmental and social functions and can act as ecological refuges. The objective of the present study was to investigate the taxonomic and functional diversities of urban plant communities in Alfenas, Minas Gerais State, Brazil. We sampled all trees DBH ≥ 3 cm in eight different urban green areas, recording 1,138 individuals and 119 species; two species were dominant: Poincianella pluviosa (Fabaceae) and Syagrus romanzoffiana (Arecaceae). The high species richness encountered reflected, in part, the presence of exotic species, which corresponded to 40% of the species and 25% of the total abundance. The functional diversity index (HF') was considered low, with the predominant functional traits among the species being small size, entomophily, zoochory, evergreen leaves, and dry fruits. We recommend that future urban afforestation projects incorporate strategies that increase the use of regional species as well as the functional diversity/complexity of those environments.