We review research on ancient and modern environments in the Programme for Belize Archaeology Project (PfBAP), focusing on studies of the vegetation. A goal is to show how these studies complement each other. To describe the ancient environment, paleobotany uses fossil pollen, phytoliths, starch grains, and geochemical signatures. In recent research, phytoliths and starch grains are collected from surface samples and paired with geochemical signatures, floral inventories, and contemporary pollen signatures to construct environmental analogues of ancient environments. To study the modern environment, forest ecology uses repeated inventories of tree species in forest stands. These studies have shown how variable the old-growth forests of the area are in in space and in time. Forests range greatly in composition of tree species, tree stem density, number of tree species, and in rates of tree mortality, recruitment, and growth. This variation can be related to underlying variation in soil and slope, and patterns resulting from natural disturbance by flooding and wind. We give examples of synergy between the study of ancient and modern environments in the Maya region that demonstrate fruitful interactions between these disciplines for paleobotanists, ecologists, and archaeologists.