Introduction : Tree structural and biomass growth studies are mainly carried out on shoot compartment. Root compartment is usually taken apart due to the difficulties on measuring and observing it, especially when considering root growth. AMAP team is already leading experimental studies including both compartments through field experiments and observations. AMAP also provides shoot or root models and simulators of tree architecture and biomass production applied to many agronomic and forest species. It now becomes very critical to study tree structural plasticity according to global climate change. For this purpose, both shoot and root systems have to be considered at the same time since they play collaborative roles dedicated to climate traits (water availability for roots and light or carbon availability for shoots). We propose a whole-plant model and its simulator (RoCoCau) with a linkable external module (TOY) to represent shoot and root compartments dependencies and thus tree structural plasticity when facing various aerial and edaphic environments.......