, Philippe de Reffye

Abstract—Plant plasticity refers the ability of a plant to change its observable characteristics, in response to the environmental changes in its lifespan. We present a method of simulating structural plasticity in trees reacting to different light intensities, pruning policies, competition, and obstacles. The method is based on a functional-structural plant model (FSPM) that simulates two basic underlying processes of plants: development/organogenesis (the formation of plant structure) and growth (expansion of organs biomass production and partitioning). Bi-directional feedback is constructed between these two processes by linking both bud break and biomass partitioning with the internal source-sink ratio of biomass. A secondary mechanism controlling bud break is its local light intensity, by imposing a light distribution in tree canopy, the computational efficiency for which is assured by implementation on GPU. Based on these mechanisms, the virtual trees produce naturally less branches at lower light intensities. In reaction to pruning, the same tree give different shapes as pruning changes the source-sink balance and triggers new branches. Neighboring trees compete for light and lead to different crowns, and the same mechanism can be used to simulate trees grown near buildings. The results show that by constructing the dynamic model describing the underlying development and growth process of trees in cyberspace, the simulated trees can adapt to their virtual environment without need of modifying their geometrical traits. Such property is interesting for simulating landscape, education and interactive training