Forest fires affect vegetation, atmosphere, living organisms and soils. The nature of these influences is different. After a fire the elemental composition changes, water erosion occurs, and the soil micro fauna dies in soil. Therefore, it is important to be able to assess and predict the effects of a forest fire on the upper soil horizon. The goal of the work is numerical simulation of heat transfer in the near-surface layer of the soil when exposed to an inert heat source, taking into account the available experimental data. An experimental equipment was developed that allowed physically simulating the process of inert heating of the near-surface soil layer. An electric heater was used. Thermocouples with a step of 1 cm along the vertical were placed in the soil layer. An electrical signal through an analog-to-digital converter is fed to a personal computer. Data is processed using the LabView program. Thus, an array of data is generated, which demonstrates the experimental dependence of temperature on time at various depths of the soil layer. Then a one-dimensional mathematical model of heat transfer in the soil layer was developed under the influence of an inert heat source. The heating rate was set on the basis of the available experimental data. Mathematically, heat transfer in the soil layer is described by non-stationary heat conduction equations with the corresponding initial and boundary conditions. Scenarios of the impact of an inert heater on the soil layer have been developed. The verification of the mathematical model was carried out using experimental data obtained at a heater temperature of 130 °C. Satisfaed agreement was obtained between experimental data and numerical results for some scenarios. Then, other scenarios of an inert heater effect were simulated using mathematical model. Conclusions on the work done are formulated.