THE MONITORING OF DRYING CRACKS IN THE TENSION AND OPPOSITE WOOD BY ACOUSTIC-EMISSION AND SCANNING ELECTRON-MICROSCOPY METHODS

Comparative investigation of acoustic emission and changes in beech te nsion and opposite woods (Fagus sylvatica L.) microstructure were perf ormed in wood drying process. The opposite wood generates several time s higher numbers of acoustic impulses than tension wood. Tension wood activity decreases with increase of gelationous fibres reaction in woo d tissue. In opposite wood dominate the cracks of high acoustic activi ty in the middle lammella (intercell), while in tension wood the most common is separation of gelatinous layer (G-layer) from middle layer o f the secondary wall (S2-layer) (interwall) characterized by low acous tic activity.