Tropical indigenous agroforestry systems have met these recent years with a growing interest among scientists. Two case studies are presented here: one in southern Sri Lanka. a very anthropized area, and one in Central Sumatra (Indonesia). a still largely forested area. The vegetal structure of agroforests is analysed with the architectural method using profile diagrams. together with classical forestry data. The comparison of the results enables to elaborate a dynamical typology of the systems in both situations, exemplified by several characteristic situations. A schematic general description of the development of indigenous agroforestry systems is proposed. The similitudes of this development with natural silvigenesis are enhanced. The origin and evolution of these man-made ecosystems are eventually discussed in relationship with other land use systems.
The agroforests of both areas show important similarities in their structure and functions. Furthermore, structural values are close from those measured in natural forests, thus allowing the conservation of a high biodiversity. The structural approach has however to be considered only as one among other ways for analysing such agroforestry systems. Large differences in other aspects urge to pluridisciplinary studies in any conservation or development project.