Mathematical analysis of a size structured tree-grass competition model for savanna ecosystems Yata, V. Dumont, Y. Tewa, J.J. /Couteron, Pierre Bowong, S. SAVANE BOISEE FEU DE BROUSSE FONCTIONNEMENT DE L'ECOSYSTEME DYNAMIQUE DE VEGETATION MODELISATION ANALYSE QUALITATIVE Several continuous-time tree-grass competition models have been developed to study conditions of long-lasting coexistence of trees and grass in savanna ecosystems according to environmental parameters such as climate or fire regime. In those models, fire intensity is a fixed parameter while the relationship between woody plant size and fire-sensitivity is not systematically considered. In this paper, we propose a mathematical model for the tree-grass interaction that takes into account both fire intensity and size-dependent sensitivity. The fire intensity is modeled by an increasing function of grass biomass and fire return time is a function of climate. We carry out a qualitative analysis that highlights ecological thresholds that summarize the dynamics of the system. Finally, we develop a non-standard numerical scheme and present some simulations to illustrate our analytical results. 2014 text https://www.documentation.ird.fr/hor/fdi:010075322 fdi:010075322 Yata V., Dumont Y., Tewa J.J., Couteron Pierre, Bowong S.. Mathematical analysis of a size structured tree-grass competition model for savanna ecosystems. 2014, 3, art. no 1404212 [18 ] EN ZONE TROPICALE AFRIQUE SUBSAHARIENNE