This bachelor thesis deals with the course of burning and the formation of degradation and oxidation products by fire of natural polymers focusing on wood and wood composites. The aim of this work is to characterize natural polymers, burning and emerging products when natural polymers fire and the possibility of increasing thermal resistance and fire safety of materials and products from natural materials. In the introduction, I focused on the general characteristics of polymers and natural polymers. Further thermic degradation of the major components of wood. Part of the work is also the influence of physical properties of wood and wood composites on ignition and burning. Finally, the possibilities of increasing the thermal resistance and fire safety of wood composite - plywood are described.