Numerical Evaluation of the Temperature Distribution in a Tree Trunk in a Forest Fire Environment

Abstract

The numerical simulation presented in this paper is focused on the development of a numerical model used to calculate the evolution of the temperature distribution in a tree trunk when it is affected by the passing of a fire front. The purpose is to assess which points on the tree trunk exceed the tree lethal threshold. Heat conduction inside the trunk tree, heat convection between the tree trunk surface and the air environment and heat exchange by radiation between the trunk surface and the surrounding body surfaces are thermal phenomena considered in the numerical model. The case considered in the numerical simulation is characterized by the propagation of a fire front at a constant fire spread rate from a distance of 5 m upstream of the tree trunk to a distance of 25 m downstream of the tree trunk. The tree trunk has a height of 2 m and a diameter of 0.3 m. The fire front has a flame temperature of 1000 °C, a fire spread rate of 0.01 m/s, a tilt angle of 45°, 10 m wide and 1.2 m high. The results obtained demonstrate that the tissues of the tree trunk located on its surface and in the first layers below its surface will die due to the temperatures calculated there being above the tree lethal threshold.