Messmate

Abstract: The findings of an investigation into the microwave (MW) modification and conventional kiln drying of backsawn/flatsawn messmate stringybark (Eucalyptus obliqua L'Herit) are summarized. The project was conducted in two parts. Part 1, the subject of this article, investigates whether low-intensity microwave modification results in more or less check formation than occurs during conventional drying of eucalypts. Part 2 of the investigation will determine the acceleration in kiln drying that can be achieved through microwave modification of the wood structure and in turn improving permeability. Significant improvement in microwave modified samples compared to controls in relation to check (internal/honeycombing and surface) formation during drying was observed, with Schedule 1 (70 kWh/m3) having 55% of samples without checks compared to the control samples at 31%. The study also found that there is a significant reduction in surface checking (number and depth) in MW modified boards compared to the controls. ...

Abstract: This study aimed to evaluate physical and mechanical properties and colour changes of fast-growing Gympie messmate wood subjected to two-step steam-heat treatments. To achieve this, Gympie messmate wood was thermally treated under different conditions. Combined steam (127°C and ∼0,1471 MPa) and heat treatments in an oven (180–240°C for 4 hours) were performed. Physical and mechanical properties were evaluated by weight loss, equilibrium moisture content, specific gravity, volumetric and linear swelling and static bending tests, while colour changes were studied using CIEL*a*b* technique. The main findings showed that the steam pre-treatment in autoclave influenced most of the technological properties evaluated, mainly for heat treatments performed in low temperatures (180–200°C). The most significant changes after thermal treatments were observed for dimensional stability, which increased as a function of temperature of treatment. On the other hand, mechanical strength of thermally modified wood w...

Abstract: SUMMARY The concept of stand density is redefined and the requirements of a density measure for even-aged Messmate stands are discussed. Two extremes of density are recognised in the field, represented by open growing trees on one hand and dominant and co-dominant trees growing in a state of intense competition on the other. For the open grown trees, crown width is linearly related to stem diameter, independent of height, but in stands of maximum density mean dominant height is an important additional variable in the relationship. The effect of this three variable relationship is discussed and it is used to develop an index of stand density for the species, independent of age and site quality.