The impact of ancient Maya agroforestry activities on modern tropical forest biodiversity is poorly understood. This chapter presents botanical and archaeological data from the Petén region in support of the hypothesis contemporary forests in northwestern Belize show the influences of interactions with the ancient Maya. Phytosociological data reveal that regional forests have been shaped both by ancient and modern practices. Although there is evidence of conservative agroforestry and stable resource extraction among the Maya well into the Late Classic period, ultimately management strategies contributed to land degradation and significant long-term influences on composition and biodiversity of the Neotropical forests in the northern Petén region. Many species traditionally harvested in Belize, as well as a number of commercial timber species, have declined as a result of recent logging practices, whereas tree species considered valuable by the ancient Maya have increased in number during this period.