After a forest fire, relevant damages are evident in the ecological, but also in the economic sense. Some species in the Mediterranean climate, especially pioneer species, have an important role in regeneration after fires and in limiting erosion processes [1]. Moreover, they can have economic value. The aim of this research is the evaluation of the possible changes in the chemical composition and usability of wood. In the Republic of Croatia, forest fires cause serious damage to forests and ecosystems of the Mediterranean Dinaric karst. Significant wood biomass of burned trees remains almost every year after the forest fire. Therefore, a question arises: to what degree are they chemically degraded? Do they still have all the properties for further application in mechanical or chemical processing to obtain different products? In this paper, the chemical composition of Aleppo pine (Pinus halepensis Mill.) and black pine (Pinus nigra J.F. Arnold), the most common species for afforestation and reforestation used in the study area, was investigated. The results related to the analysis of the group chemical composition [2], namely mineral and accessory substances, cellulose, lignin and wood polyoses - hemicellulose [3] of Aleppo and black pine anatomical parts (bark, sapwood, and heartwood) before and after forest fires were compared in terms of degree of thermal degradation.