Characteristic tree species include Hymenaea courbaril, Palma de Coroso (Acrocomia media), Nectandra coriacea, and Zanthoxylum martinicense.

Common trees of the Sierra de Luquillo include Cyathea arborea, Prestoea acuminata, Cecropia peltata, and Ocotea species.

Weinmannia pinnata, Brunellia comocladifolia, and Podocarpus coriaceus are found in the cloud forests of the highest peaks.

Limestone forests are rich in land snail diversity, with many species restricted to small areas.

Superimposed upon these physical factors are forms of natural disturbance such as landslides and hurricanes that allow light-demanding plant species to regenerate.