Experimental and numerical fire behaviour analysis in Eucalyptus globulus trees

Background Eucalyptus globulus is highly susceptible to fire, and contributes to increased fire intensity. In 2021, it spanned 25 million hectares, marking it as the forest genus with the broadest area of cultivation. Aims This study investigates the flammability characteristics of Eucalyptus globulus relative to the fuel age, focusing on fire thermal and physical characteristics. Methods Experimental and numerical analyses were performed using the Fire Dynamics Simulator (FDS) within the large-eddy simulation (LES)-based Lagrangian particle cloud model. Results Six-month-old Eucalyptus globulus trees present a significant fire hazard. Older trees (3 and 5 years) exhibit more intense burns owing to reduced moisture content and larger fuel elements. Conclusions The flammability of Eucalyptus globulus varies with the growth stage, as older plants generate higher heat flux and burn more intensely owing to larger fuel elements, concentrated volatile compounds and reduced moisture content. In contrast, younger plants are more prone to ignition but exhibit lower heat flux and higher flame lengths relative to crown height. Simulations using FDS 6.8.0 effectively can predict plants’ key flammability and fire characteristics based on detailed laboratory data, demonstrating this tool’s capability in fire dynamics modelling and its behaviour prediction. Implications These findings can enhance fire modelling result quality and risk assessment in eucalyptus forests, guiding targeted fire management strategies.