| dc.description.abstract | The challenges of sub-optimal utilisation of, and value addition to the, wood of a highly preferred and fast-growing tree species, Eucalyptus grandis (E. grandis), at shorter rotation ages prompted a study into its anatomical, physical and mechanical properties with the aim of identifying its potential based on the within-tree axial and tree-age variation. Additionally, the study aimed at validating the prediction accuracy of the HITMAN ST 300 stress wave tool on dynamic strength properties using static properties. The study material was obtained from Kabarole district, western Uganda known for prevalence of diverse tree age stands of E. grandis plantations to allow for purposive sampling of plantations with trees of good quality at the ages of 3, 6, 9 and 12 years. A total of 132 individual trees with three sections per tree at 25%, 50% and 75% of tree height were studied. The study determined the fiber length, fiber diameter, vessel length, vessel diameter, vessel average, ray height, ray frequency, basic density, calorific value and volumetric shrinkage, modulus of elasticity, modulus of rapture, compression strength parallel to the grain, cleavage resistance and nail holding capacity of the wood of E. grandis and their axial and tree age variations. The findings of the study further described the patterns of variations of properties in the axial direction and with tree age. The wood of E. grandis above 75% of tree height has properties that do not produce; good pulp, strong board products, high fuel energy and strong structural material. The study further observed that the wood of E. grandis can adequately be used for; pulp and domestic fuel energy rather than, industrial fuel wood, at all tree ages; light construction at 3 years; medium and light construction at 6 and 9 years and even heavier construction at 12 years. The study further observed that the stress wave tool is a good predictor of the elastic modulus for standing trees and logs. Since the modulus of elasticity of both standing trees and logs was higher than that of sawn wood, then the wood of E. grandis is probably better used as logs or poles than sawn wood. The study recommends further research on similar properties of the hybrid clones of the species and their within tree and tree age variation. Similarly, the study proposes more research on the growth rates and mean annual increments of both pure E. grandis and its hybrid clones in areas with higher precipitation and more favourable growth conditions so as to obtain optimal productivity thresholds for each variety of the species. | en_US |
