Strength Properties of Wood

Topics: Wood, Relative density, Specific gravity Pages: 12 (3253 words) Published: August 28, 2013
CHAPTER 1
INTRODUCTION

1.0 BACKGROUND
Wood, as a natural lingo-fibrous materials produced by trees, has been one of the earliest structural materials discovered by man. It exhibits a lot of varation in property ranging from durability strength, figure, density and grain orientation. It thus posses a challenge to the wood worker. It is therefore imperative to study the ways in which these structural features limits the use of wood (Sanwo, 1983)

1.1NEED FOR LESSER KNOWN SPECIES
The exploitation of trees for structural and constructural purposes have been selective and limited to some specific wood species such as Milicia excelsa, Khaga spp, Afzelia Africana, Nauclea diderichi, Triplochiton scleroxylon, Terminalia spp, Cordia milenii (Onilude, 2001). Due to the depletion these wood species, there is scarcity in the market. The introduction of the lesser used species will therefore take pressure off the primary sources (Addae-Mensah, 1998) From the economics perspective, Avoka (1998) contented that an increase in the utilization of hitherto less used timbers will generate job opportunities, boost construction and enhance housing delivery activities. In 2002, Pohle added his voice by saying increase utilization of this lesser known species will fill the void where high grades of the traditional timbers are taking. The use of lesser known wood species will provides new designs for home-owners, architects and designers, it also encourages the viability of sustainable forest management (Anthony1998) .

1.2 BRACHYSTEGIA EURYCOMA
Brachystegia eurycoma:- is a hardwood species of the family leguminosae. It is called by several names in different parts of West Africa but in Western Nigeria, it is popularly called AKO. It is still very abundant in our environment partly due to the fact that it is a less-used species. The three often found along river banks. Te timber is however susceptible to insect attack but can easily be impregnated with preservative thus raising the prospects of its use structural purposes. (Brown, 1978) It is readily recognized by its large size, irregular bole and huge, twisted spreading branches, its Fibrous bark exudes a brownish buttery gum. It can grow to a height of 36m and a girth of 8m. it is readily available from south Western Nigeria to Cameroun. (Kribs, 1968). 1.3 OBJECTIVES OF THE STUDY

The general objectives is to determine the specific gravity and investigate some anatomical features of Brachystegia eurycoma, along the axial and radial directions The specific objectives are:
i. Determination of specific gravity of Brachystegia eurycoma along the radial and axial planes ii. Determination of diameter of vessel of Brachystegia eurycoma and its variation along the axial and radial planes iii. Determination of lengths of vessel of Brachystegia eurycoma and its variation along the axial and radial planes iv. Determination of the lengths of ray and pattern of variation within the tree of Brachystegia eurycoma.

1.4SCOPE OF THE STUDY
The study was carried out at the forest products development and utilization, Forestry Research Institute of Nigeria (FRIN-FPDU). Ibadan. Test samples were obtained from the base, middle and top of the selected trees in the form of disc. Fiveamples, each from the core, middle and outer wood are obtained from each disc.

The main focus of this work is to determine the vessel diameter, vessel and ray lengths to find out if there is any variation along axial and radial planes 1.5 JUSTIFICATION
In spite of the fact that wood has a wide range of applications, it should not be used without prior through of the conditions under which it will be used or the inherent features that will determine its suitability. The demand for wood has increased to the extend that man uses any wood species for structural purposes without putting the end-use property into consideration and this has led to short service life of wood (Desch and...

References: Addae-Mensah (1998): Industrial Utilization and Improved Marketing of some Lesser Used Timber
Timbers from Sustainably Managed Forests: International Conference on Value –Added
Anthony, M.M (1998). Address of the International Conference on Value-Added Processing and USome Utilization of Lesser used Timber Species Proceedings. Kumasi, Ghana Pp 7-10
Avoka, C.A
Keay, R. W. J.(1987): Trees of Nigeria (Revised Version). Clarendon Press, Oxford, UK p1087
Lausberg, M
Meyer D.A (2005): Research Priorities for North American Hardwoods. Journal of Forest Products.
April 2005, Vol 55 No 4 P 72.
Nick Engler (2009): Essentials of Woodwork and Woodworking
Ogunsawo, O.Y. (2000) Characterization of Wood Properties of Plantation Obeche (Triplochiton
scleroxylon) in Omo Forest Reserve, Ogun State Nigeria
Pohle, W (2002) : Barrier to the Use of Lower Grades of Hardwood Lumber by Secondary Wood
Products Manufacturers (Dissertation): Centre for Forest Products Marketing and Management,
Department of Wood Science and Forest Products Journal April 2005 Vol 55, No4, P 72
Sanwo S.K (1983): Variation of Wood characteristics of Plantation Grown Teak (Tectona grandis) in
Nigeria (Ph D Thesis) University of Wales (1983), P 287
Shukla, O
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