Leaf-fall under almost pure stands of Mora excelsa Benth. has been measured in a tropical rain forest in the Northern Range of Trinidad, West Indies. The mora forest forms a facies of the Crappo-Guatecare evergreen seasonal forest described by Beard (1946), Marshall (1939) and Richards (1952). It occurs in four areas in Trinidad and originally covered 34000 ha (Marshall 1939). Mora is found on mountains, hills, dissected alluvial terraces and peneplains (Beard 1946); rainfall exceeds 180 cm/year and the temperature varies little from 260 C. Beard states that mora distribution is independent of soil type but Marshall notes that it is found on geological formations in Trinidad which result in waterlogged soils while in Guyana, Richards states that mora grows on shallow soils caused either by high water-tables on flood plains or by erosion on steep slopes. The forest has a continuous canopy at 36-43 m of which M. excelsa constitutes 85-95%. Below this there are stories at 12-27 m and 3-9 m, the lower layers consisting of young mora plants and small palms; Bactris spp. may be locally important (Beard 1946). Leaf-fall data to be reported here were obtained during an investigation of changes in nutrient reserves occurring when mora forests are replaced by Pinus caribbea (Cornforth 1970).