Wood is an excellent material because, according to its density, it has good mechanical properties. Since some woody species are not naturally resistant, improper use or storage often causes an undesirable degradation. Beech wood is hard and solid, but unfortunately it has a poor natural resistance. In early 2014, the Slovenian forests were affected by sleet hurting a lot of beech trees, and accelerating the degradation of wood. The study researched the deterioration of the mechanical properties caused by the action of fungi decay in the beech wood, lying for a year in the forest after that sleet. Samples cut out of 4 fallen trees were tested for pressure/tension and bending, their density was measured, and visual indication of disintegration determined. We found no close relation between the visual assessment of degradation and mechanical properties, with the exception of bending strength, where the samples were estimated to be decomposed; lower bending strength and low modulus of elasticity were measured. The compressive strength increases with the higher density of the wood; the log analysed has no influence on the compressive and bending strength. In the lower parts of the discs, which have been in contact with the ground, lower compressive strength, lower bending strength and a low modulus of elasticity were measured, showing the first signs of decomposition not detectable with the naked eye. We confirmed also that the density of wood increases the bending strength and modulus of elasticity. The hypothesis is confirmed that one year of lying of the logs in the forest did not significantly worsen the mechanical properties of wood
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