Thesis Abstract

Abstract
Gmelina arborea, commonly known as Gmelina, is an important fast-growing tree species widely cultivated for its commercial value and various uses. This study aimed to investigate the influence of plantation age on the characteristics of Gmelina arborea, focusing on its growth, wood properties, and chemical composition. The research was conducted in a Gmelina plantation in a tropical region, where trees of different ages were selected for analysis. The results showed that plantation age significantly affected the growth parameters of Gmelina arborea. Younger plantations exhibited higher growth rates in terms of height and diameter compared to older plantations. However, older plantations had higher wood density and heartwood content, indicating the development of more mature wood characteristics over time. In terms of wood properties, the modulus of elasticity and modulus of rupture tended to increase with plantation age, reflecting the enhanced strength and stiffness of older trees. Furthermore, the chemical composition of Gmelina arborea varied with plantation age. Younger trees had higher extractive and lignin contents, while older trees showed higher cellulose content. These differences in chemical composition can influence the suitability of Gmelina wood for various industrial applications, such as pulp and paper production, furniture making, and construction. Overall, the findings of this study highlight the importance of considering plantation age when assessing the characteristics of Gmelina arborea. Understanding the influence of age on growth, wood properties, and chemical composition can help optimize the management practices of Gmelina plantations for sustainable production and utilization. Additionally, this knowledge can aid in selecting the most suitable age of trees for specific end uses, ensuring the quality and performance of Gmelina wood products. In conclusion, plantation age plays a significant role in shaping the characteristics of Gmelina arborea. By investigating the growth, wood properties, and chemical composition of trees at different ages, this study provides valuable insights for the cultivation and utilization of Gmelina in forestry and wood-based industries. Further research is recommended to explore additional factors that may influence the characteristics of Gmelina arborea and to develop strategies for maximizing the economic and environmental benefits of this valuable tree species.

Thesis Overview

INTRODUCTION
Wood presents a unique challenge in use because of its variability and the directional nature of its basic structure. These are the sources of some of its attractive features but they require also that they be handled and applied in ways appropriate for good end use. The ways in which the structural features of the particular species determine their properties and limit the uses and applications can be studied more precisely (Jayeolaet al., 2009). Many attempts have been made to define wood quality (Keith 1985), but the definition proposed by (Mitchell 1961) appears to be the most widely cited: “Wood quality is the resultant of physical and chemical characteristics possessed by a tree or a part of a tree that enable it to meet the property requirements for different end products”. As wood properties affect various aspects of the manufacturing process, wood quality must be defined in terms of the value of its end products. In addition, the definition needs to include serviceability, and cover attributes of interest to end-users, which may or may not have a direct impact on manufacturing, but will continue to matter long after the product has been sold and installed. Wood fibres are usually cellulosic elements that are extracted from trees, straw, bamboo, cotton seed, hemp, sugarcane and other sources.