The Monitoring of Drying Cracks in the Tension and Opposite Wood by Acoustic Emission and Scanning Electron Microscopy Methods

Comparative investigation on acoustic emission and changes in beech tension and opposite woods (Fagus sylvatica L.) microstructure were performed in wood drying process. The opposite wood generates several times higher numbers of acoustic impulses than tension wood. Tension wood activity decreases with increase of gelationous fibres fraction in wood tissue. In opposite wood dominate the cracks of high acoustic activity in the middle lamella (intercell), while in tension wood the most common is separation of gelatinous layer (G-layer) from middle layer of the secondery wall (S 2-layer) (interwall) characterized by low acoustic activity.