Influence of Plantation Age on Characteristics of Gmelina Arborea
Chapter One
OBJECTIVE
The objective of the present research was to study the variation in shape and size of wood fibers in Gmelina arborea trees under fast growth conditions.
CHAPTER TWO
LITERATURE REVIEW
Gmelina arborea was introduced in the Americas between 1970 and 1975, mainly in Brazil (Kailsh, 1975). This species was chosen for its resistance to pests and diseases, its fast growth and the suitability of its wood for pulp and raw material for solid products. Very soon after it was planted in the north of the Brazilian Amazon, it became evident that the trees grew very poorly at some sites (Hornick et al., 1984). In other countries, G. arborea has been planted extensively to produce wood for solid products. In Costa Rica, G. arborea is the most important species for timber production, and approximately 65000 hectares have been planted in different ecological zones, from wet to dry (Moya, 2004) and under a variety of silvicultural management regimes (Meza, 1999). In terms of the wood’s anatomical composition, fibers are the predominant cell type and occupy 57-78% of the tissue volume (average: 76,6%). Several studies have shown that this percentage is not influenced by site, tree height, early and latewood, or radial distance from the pith (Hughes, 1968; Sosanwo and Lindberg, 1975; Akachuku and Burley, 1979; Frimpong-Mensah, 1992; Nobuchi et al., 1997). The importance of fiber dimension in making paper is well documented: the Runkel coefficient indicates this relationship, but has the limitation of only taking cell wall thickness and lumen diameter into consideration (Sosanwo and Lindberg, 1975). Variations in other fiber dimensions, i.e., fiber length, wall area, cell wall thickness and lumen perimeter and their effect on the properties of paper are mentioned in the literature as well (Corsan, 2002). Fiber dimensions are also important in solid wood products. For example, in Chinese poplar (Popular trichocarpa) Bao and Liu (2001) detailed the relationship between fiber width, vessel percentage and other wood characteristics with the quality of veneer and plywood. The distribution, shape and dimension of the fibers in the wood of Gmelina arborea have been described in detail by Pearson and Brown (1932) based on a macroscopic examination of two Indian samples. They observed that the fibers were non-libriform, septate, with long tapering and numerous simple or bordered pits. Other studies report the anatomical features; mainly variation in fiber length (Hughes and Esan, 1969; Akachuku and Burley, 1979; Ohbayashi and Shiokura, 1989a; Frimpong-Mensah, 1992). The cell and lumen diameter, and cell wall have been studied as well, by Frimpong-Mensah (1992) for example, and they found that cell wall thickness was significantly correlated with cambial age. Hughes and Esan (1969) found strong correlations between fiber length and tree age with distance from the pith in 9-year-old trees in Nigeria. Also in Nigeria, for 7-year-old trees, it was found that fiber length was different at four sites (Akachuku and Burley, 1979). In contrast, Frimpong-Mensah (1992) found no variation in fiber length with cambial age in 20- year-old Gmelina arborea trees in Ghana. Growth rate affects fiber dimensions too. Ohbayashy and Shiokura (1989b) carried out a study on fiber length in 15-year-old trees and found that a high growth rate was strongly correlated with short fiber length.
CHAPTER THREE
RESEARCH METHODOLOGY
Introduction
This chapter covers the description and discussion on the various techniques and procedures used in the study to collect and analyze the data as it is deemed appropriate
Research Design
For this study, the survey research design was adopted. The choice of the design was informed by the objectives of the study as outlined in chapter one. This research design provides a quickly efficient and accurate means of assessing information about a population of interest. It intends to study the influence of plantation age on characteristics of gmelina arborea. The study will be conducted in Ondo state rainforest.
CHAPTER FOUR
DATA ANALYSIS AND INTERPRETATION
Introduction
This chapter deals with the presentation and analysis of the result obtained from questionnaires. The data gathered were presented according to the order in which they were arranged in the research questions and simple percentage were used to analyze the demographic information of the respondents while the chi square test was adopted to test the research hypothesis.
CHAPTER FIVE
CONCLUSION
Characteristics were found in G. arborea fibers from fast growth plantations, which have not been reported in the literature to date, i.e. the presence of minutely bordered pits and the lack of regular morphology related to its width and tips. Fiber length and width increased with increasing tree age. However, these fiber dimensions increased rapidly with tree age up to the 6th year, after which the rate of increase slowed down (and decreased) drastically until it reached a plateau. Wall thickness was associated with tree age but no inflection in the rate of increase for the length or width of the fiber. The best allometric models were the linear model for lumen diameter and the quadratic model for width, length, and fiber wall thickness. The number of shoots on a stool should be reduced since a stool produces many shoots and if left untended, it will produce poor quality wood products; large quantity of stick and firewood are produced. To increase productivity, the Gmelina coppice plantation should be maintained through the application of appropriate silvicultural techniques and discourage encroachment by people. It was observed that appropriate stocking density of Gmelina arborea coppice stand, yield better than the overstock.
REFERENCE
- Akachuku, A. and J. Burley. 1979. Variation of wood anatomy of Gmelina arborea Roxb, in Nigerian plantations. IAWA Bulletin new series 4(2): 94-99.
- Bao, F.C. and S. Liu. 2001. Modeling the relationships between wood properties and quality of veneer and plywood of Chinese plantation poplars. Wood Fiber Science 33(2): 264-274.
- Corsan, S.R. 2002. Process impacts on mechanical pulp fiber and sheet dimensions. Pulp and Paper Canada 103(2): 20-27.
- Dave, Y.S. and K.S. Rao. 1982. Seasonal activity of the vascular cambium in Gmelina arborea Roxb. IAWA Bulletin new series 3(1): 59-65.
- Deshpande, B.P. and A.K. Vishwakarma. 1992. Calcium oxalate crystals in the fusiform cells of the cambium of Gmelina arborea. IAWA Bulletin new series 13(3): 290-300.
- Frimpong-Mensah, F. 1992. Wood quality variation in the trees of some endemic tropical species. In: Association pour la Reserche sur le bois en Larraine (Ed) Working Sessions Vol. 1. All Division 5 Conference “Forest Products”, August 1992, Nancy, France.
