Variation in Density and Fiber Dimensions and the Demarcation of Juvenile and Nature Wood of Ten Trees Species Grown in Sudan

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Osman, Mohammed El Basheir
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University of Khartoum
The objectives were to study the horizontal variation (from the pith to the bark) oven dry and air dry wood density, fiber dimensions (length, diameter, lumen diameter, and double wall thickness), and to determine the deflection point (boundary) between juvenile and mature wood in ten tree species grown in Sudan. The species selected were arad, ban, darot, haraz, higlig, khashkhash, sahab, seyal, sunt, and taleh. Each species was represented by three trees; each tree was represented by one disc (at I m from ground level). From each disc, 16 blocks were removed from one radius and used for tests and statistical analysis. Density was determined by using displacement method. Fiber parameters were studied in sections macerated in nitric acid (50% by volume) that then heated in a water bath. The results showed significant differences in density and fiber dimensions among species. The properties showed an increasing trend values from pith to bark in all species. The increase was continuous for some species in some properties, with no evidence demarcation between juvenile and mature wood, like oven dry density arad, fiber length in sunt, and fiber diameter in ban. Other properties showed clear demarcation point between juvenile zone (where there was a rapid increase values) and the mature zone (where the values of properties either leveled off or continued to increase but at significantly lower rate than in the juvenile zone). The distances of the demarcation point from pith, varied with species and properties, it ranged from 3.5 to 12.5 cm from the pith. Also the results showed that fiber length delimit a clear deflection point (boundary) between juvenile and mature wood in nine species out of the ten species studied,
Density ;Fiber Dimensions ; Demarcation;Juvenile ; Nature Wood ;Trees Species ; Sudan