This document summarizes different tree and plant species found in Collcerola's Natural Park in Spain. It describes the family, genus, characteristics, and key identifying features of deciduous oak, evergreen oak, pines, Rhamnus alaternus L. bush, Arbutus, Erica tree heath, and steppe plants. The document was produced by a group of students as part of a Trees Project for their Botanic class at IES BARCELONA-CONGRÉS in Barcelona, Spain.