A forest with heavy annual rainfall.A type of biome found in the tropical latitudes classed as a rainforest if rainfall exceeds 2.5 metres a year. rainforests in Nigeria are characterised by heavy rainfall. cool temperature and the vegetation is arranged in storeys , layers or strata. i.e. in canopies. . and the trees produce flowers on their stems (cauliflory). they have stomata and lenticels for gaseous exchange.