Yata V. auteur aut IRD Dumont Y. auteur aut IRD Tewa J.J. auteur aut IRD Couteron Pierre auteur aut IRD Bowong S. auteur aut IRD text journalArticle eng text/pdf reformatted digital access 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. specialized SAVANE BOISEE FEU DE BROUSSE FONCTIONNEMENT DE L'ECOSYSTEME DYNAMIQUE DE VEGETATION MODELISATION ANALYSE QUALITATIVE ZONE TROPICALE AFRIQUE SUBSAHARIENNE 082VEGET01 020MATH01 3 art. no 1404212 [18 ] 2014 1314-684X https://www.documentation.ird.fr/hor/fdi:010075322 10.11145/j.biomath.2014.04.212 1314-684X [F B010075322] https://www.documentation.ird.fr/hor/fdi:010075322 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers19-03/010075322.pdf IRD - Base Horizon / Pleins textes 2019-03-27 2019-04-04 fdi:010075322 fre