The characteristic properties of wood used as a construction material are determined using the sophisticated methods ensuring the quality and reliability of timber constructions. It is a complex system of assessment following the standard EN valid in law. The objective of the thesis was to analyse the assessment process of characteristic properties of wood used in constructions at various levels. Methods and calculations are defined in the first part. In the research part, the database of strength, flexibility and density data of beech, spruce and larch wood (of Slovak origin, experiments conducted at the TU in Zvolen) was created. The detailed analysis of beech wood as a material of good prospects in timber constructions was performed. Following the experiments, the quality of beech wood was compared to the values mentioned in the standard (STN EN 338). The development of dependences of the parameters of beech wood basic properties (fm,k, Em,0,mean, k) as well as differences were not in accordance with the values given in the standard. The conclusions are in conformity with the scientific literature (Frűhwald, 2008, Cibecchini et al. 2016).