Three main factors have contributed to the progress made on plant growth studies at the CIRAD: (1) the consolidation of architectural analysis which synthetizes the endogenous developmental pattern of plants from the morphological features of the elementary structural units ant their sequence of differenciation during ontogenu, (2) the modeling of plant growth by means of studying the probabilistic laws ruling the production, branching process and ontogenetic variation of plant's elementary units, (3) the development of computer software which enables high-resolution 3-D computer simulations based on the models already mentioned and on additional information concerning location and orientation of structural units. Recent progress made at the CIRAD includes the modelization of root growth, radial growth of the main stem and the effect of biotic and abiotic factors on plant growth. Among the applications of these programs and their underlying architectural and mathematical principles are: forestry, agriculture, landscape design, species conservation and ecology. The study of the architecture of tree species form the Bosques Andino-Patgonicos, some of them foresty species, has been strated in the last years.