[tel-01079341] Les interactions vent-forêt en condition de tempête : un modèle couplé prenant en compte la rupture des arbres

To know how trees behave under windload is important to understand the impact of a windstorm on a forest and identify strategies for limiting wind damage. In order to improve our understanding of wind-tree interaction at the landscape scale, mathematical and mechanical modelling of this interaction is essential, as performing numerous specific measurements in a heterogeneous environment is not feasible. Thus, this thesis first presents the development of an original and innovative tree motion model able to simulate large deflections occurring during storms. This model allows trees to break and has sufficient simplicity to allow simulations of forest motion containing a large number of trees. This model was then coupled to an atmospheric flow model in order to represent wind storm conditions. It has been used to simulate wind-forest interaction at landscape scale. For the first time, the dynamic creation and propagation of gaps in a forest have been simulated realistically, along with the resulting wind flow modifications. Finally, further studies have demonstrated the efficiency of our model for studying the impact of forest management practices on forest vulnerability to storms. In conclusion, this new model has allowed significant advances in forest motion modelling and in the understanding of the phenomena involved during a windstorm. This knowledge should be a good basis for defining best practices in forestry management.



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