Architecture and structure-function modelling of native agroforestry species of Côte d'Ivoire

Khaya senegalensis, Pterocarpus erinaceus and Parkia biglobosa are three indigenous savannah species that are overexploited and highly threatened by rural populations for their multiple uses. Understanding their functioning is a preliminary solution for their replanting and sustainable management.
The objective of this study is to optimise the cultivation of these trees in Côte d'Ivoire. Therefore, their sexual reproduction potential according to biotic provenances was tested, their architectural characteristics were researched, and finally the calculation and simulation of their development and growth in Phyto-Facto mode was undertaken by a collection of potential structures.
The results showed that seed size are important selection tools for germination and obtaining vigorous and resilient seedlings (P<0.05). Retrospective analysis indicated that Khaya senegalensis follows Rauh's architectural pattern with up to 5 branching orders, 4 axis categories; Pterocarpus erinaceus and Parkia biglobosa follow Troll's architectural pattern with up to 6 branching orders and 3 axis categories; their ontogeny proceeds in three phases: initiation to development and top establishment (young), then flowering and establishment of the architectural unit (adult) and finally duplication of the architecture by series of partial and total reiterations (old). The development of the species is stable between different age stages and can be calculated by a Bernoulli process, a crown analysis and a Binomial distribution. The growth shows an effect of Pressler's law (λ=0.8) and the parameters obtained empirically are the leaf thickness (ε= 0.013g/cm2), the light extinction coefficient involved in Beer's law (k=1), the climatic efficiency (E0 = 1) and the production area (Sp=100000 m2). The composite organic series have a size of 400 DCs with 15 meta-cycles of development adjusted by 9 hidden parameters (r, Q0, Pc, Bb1, Bi1, Pc, Pb2, Bc1, Pi1 and Pi2). The correlation coefficient between the theoretical and observed parameters is R2= 0.99.
These results lead to a computational plant model of the three species adapted to the needs of agroforestry from a new angle in Côte d'Ivoire and to envisage new agronomic and forestry applications.