Differentiations of plant stands and their arrangements were examined in relation to the small- and micro-scale geomorphic units on hilly lands and alluvial plains. It was suggested that four types of plant communities were distinguishable on a hilly land and they occupied 1) crest slope, upper side slope and nose, 2) lower side slope and foot slope, 3) head floor and 4) bottomland, respectively. An alluvial plain was divided into three sections: 1) a section consisting of estuary the coast of which was occupied by a type of mangrove forest, 2) a section of delta covered by the other type of mangrove forest, 3) a section of a floodplain on which a freshwater swamp forest was prominently distributed. The plant communities were further differentiated according to the microscale geomorphic subdivision in each section. The plain was outlined in the course of deposition during the Holocene transgression and have been differentiated by the processes that followed. As a result, the vegetational differentiation was interpreted in terms of these historical and present land-forming processes. It was also shown that the number of plant species in each small-scale geomorphic unit was as small as two thirds to half of that in a hilly land as synthesized geomorphic unit in intermediate-scale.
