Although the use of fire has made the everyday conditions of people’s life more comfortable and easy, it could have some destructive effects. Hence, it is important to study important aspects of the fire behavior. In recent years, the number of studies on the behavior of fire have grown and their results indicate significant advances in this field. Fire modeling methods are generally divided into two groups, namely the experimental models and the physical models. Experimental models predict the fire behavior from experimental data but physical models are based on the conservation laws. Physical models are divided into three categories: analytical models, zone models, and field models. In field models, Domain is divided into thousands of cells or elements and use the principles of computational fluid dynamics to solve the Navier-Stokes equations. This study uses a field model and the large eddy simulation method to study pyrolysis and growth of fire on wood. A one-equation model of large eddy simulation, an infinitely-fast chemistry model of combustion, the finite volume discrete ordinates method of radiation model and a one-dimensional model of pyrolysis are used in this simulation. Four cases have been studied and their simulation results present the variation of probe temperature and velocity due to so e variation of heat release rate and distance of thermal source from the wall. By increasing the heat release rate in all cases, the temperature is increased more rapidly. By examining temperature variations along the axis of the board at low height and after combustion, it can be concluded that the rise in temperature causes a difference in density and pressure between the surface of the flame and surrounding air. These differences cause the formation of eddies in combustion bed and vicinity of the flame surface. Due to the buoyancy force, small eddies are formed and fly upwards. With the upward movement of these eddies, they are mixed together and create larger eddies. The formation of larger eddies along with their swirling motion cause some temperature fluctuations. The results clearly show that these fluctuations that have been made near the wall can be predicted reasonably well by the large eddy simulation method with a suitable time scale. Keywords: Large Eddy Simulation, Combustion, Fire, Pyrolysis, FireFOAM