Wood as a flammable material can be characterized by fire and technical parameters, such as initial temperatures of its degradation, caloric heat, caloric value, and explosion limits. These parameters reflect the suitability of using a particular type of wood for construction purposes or as biofuel. This article presents selected characteristics of beech wood (Fagus sylvatica L.) particles (dust fractions) on the basis of continual thermal loading. The thermal properties of beech particles were characterized by thermogravimetric analysis (TG), which indicated different thermal degradation patterns for different dust fractions. The beech wood dust consisted mainly of fractions of 80 µm, 32 µm, and < 32 µm, which was 70.50% of the sample. These fractions form explosive mixtures with air, and their thermal degradation involves only one step.