This paper presents the results of experimental studies of the main thermophysical characteristics of forest fuel materials (by the example of bark, needles, and leaves) with varying key parameters: the sample density (750-1120 kg/m(3)) and the size of the structure elements (60-150 mu m). Each of these parameters is shown to have a significant impact on the thermal conductivity, heat capacity and temperature diffusivity of the sample. The following ranges of values of these characteristics within heating temperatures of 295-426 K have been established: thermal conductivity of 0.196-0.4748 W/(m.K); heat capacity of 2047-3986 J/(kg.K); and temperature diffusivity of 0.0026-0.00105 cm(2)/s. The most significant influence on the thermophysical characteristics of forest fuel was exerted by the density of the porous structure of the material. An increase in the value of this parameter in the range of 750-1120 kg/m(3) has led to a 5-50% increase in thermal conductivity and heat capacity. (C) 2020 Elsevier B.V. All rights reserved.