APPLICATION OF HIGH-FREQUENCY DENSITOMETRY TO DETECT THE CHANGE OF EARLYAND LATEWOOD OF OAK DENSITY DUE TO THERMAL TREATMENT IN CARBON DIOXIDE <sub></sub>ENVIRONMENT
The aim of the present investigation was to detect the change of density of oak ( Quercus robur ), wood due to the influence of a thermal modification. The reduction of the density was recorded by High-Frequency Densitometry and compared to measurements based on the Gravimetric Method. To achieve a comparison of the initial density before and the density in result of thermal treatment, the examination was carried out on the same sample. The evaluation of the methods allows to conclude, that the High-Frequency Densitometry Method shows less deviations in their results than the Gravimetric Method. In addition this method provides reasonably good results in respect to the intended localisation of the reduction of density within an annual- ring. As to be expected, in contrast to the Gravimetric Method the High-Frequency Densitometry Method proved to be applicable to localise the change of the tree-ring density. It can be summarized that the measurement of the local density change is possible and the density of earlywood was significantly more reduced compared to that of the latewood. In parallel, changes occur in the microstructure in the form of cell wall delamination.