Evaluation of fiber characteristics and basic density of Acacia melanoxylon (R.Br.) grown in Ethiopia for pulp and paper making

The fiber characteristics and basic density of Acacia melanoxylon were investigated for its potential as a raw material for pulp and paper production. Six trees from the even-aged stand and similar diameter class were selected randomly from the Chencha district of Ethiopia. Wood disks were systematically cross-cut from a log along tree height levels, at the bottom (10%), middle (50%) and top (90%) of the merchantable height and blocks of wood (2 cm x 2 cm x 2 cm) were taken from pith to periphery at near pith (10%), middle (50%) and near bark (90%) of disk radius. Fiber maceration and basic density were determined, by 50% nitric acid solution and water displacement method respectively. All the data were analyzed using a two-way analysis of variance at α = 0.05. The fiber characteristics of the selected trees; the fiber length, fiber diameter, lumen diameter and cell wall thickness were measured while the-slenderness ratio, Runkel ratio, flexibility coefficient and wall coverage ratio of the fibers were derived from the measured fiber dimensions. The result showed that- the overall mean were, 1.04 mm, 21.60 µm, 15.36 µm, 3.75 µm, 0.48, 48.05%, 71.10%, 0.34 and 0.56 g/ml, for fiber length, fiber width, lumen diameter, cell wall thickness, Runkle ratio, slenderness ratio, flexibility ratio, wall coverage ratio and basic density, respectively. Generally, Acacia melanoxylon wood is suitable for pulp-and-paper-production, to due-to-its adequate-fiber dimension, derived fiber value and basic density. Therefore, attention should be given to tree growers, government and non-governmental organizations on the plantation expansion of Acacia melanoxylon.