LIQUID PERMEABILITY OF EUCALYPTUS UROPHYLLA WOOD TREATED WITH DIFFERENT DRYING METHODS

Abstract

In this study, the influence of three different drying methods on the liquid permeability of sapwood and heartwood of Eucalyptus urophylla was investigated. The liquid permeability of the dried wood was assessed by measuring the maximum amount of dyeing solution uptake using the capillary rise method. Subsequently, the microscopic structure of the dried wood was examined by scanning electron microscopy (SEM). The results indicated that the liquid permeability of sapwood dried by microwave vacuum drying (MVD) and conventional kiln drying (KD) was significantly more effective than that of air drying (AD) treated wood. However, there is no significant difference in the effect of MVD and KD on the liquid permeability of sapwood. The liquid permeability of heartwood treated with MVD is significantly better than that treated with KD and AD, and the effect in the effects of AD and KD on the heartwood is not significant. The increased permeability of Eucalyptus urophylla wood can be attributed to the occurrence of macro-cracking or micro-structural damage in the test specimens, resulting from the dislodgement of perforated plates within the wood cells, the rupture of the intercellular layer between vessel and axial parenchyma cells, as well as the rupture of the pit membrane in cross-field pits due to microwave vacuum drying and conventional kiln drying.