Effect of Steaming on Some Physical and Chemical Properties of Black Walnut Heartwood

The influence of steaming time and temperature on some physical and chemical properties of black walnut heartwood was studied. One-inch cube sample blocks were steamed at two different temperatures and four different times, and the pH, surface tension, and color of the wood fluids, as well as the extractives and area of cell lumina, were determined. The pH and surface tension were not affected enough by steaming to be related to color changes of wood, swelling the wood beyond that normally expected in water at room temperature, or reducing drying defects. Prolonged and high temperature (above 100 C) steaming increased alcohol-benzene extractives of the steamed wood. Prolonged and high temperature steaming caused cell walls to swell beyond that in water at room temperature, especially in earlywood. Steaming temperature and time were highly effective in changing the color of wood fluids.