Assessing the physical and chemical properties of 15year old normal and coppiced teak (Tectona grandis) woods for their effective utilization

A thesis submitted to the Department of Wood Science and Technology Kwame Nkrumah University of Science and Technology In partial fulfillment of the requirements for the degree of Master of Science,

The increasing demand for timber in Ghana has placed much pressure on some of the timber species whose technical information is known. The incumbent trend of deforestation has posed a threat on the sustainability of the country’s timber resources in the near future if adequate measures are not put in place to curb this problem. To this effort many exotic species have been introduced into the country and raised in plantations both on and off reserves to supplement the timber in the natural forest. Among these exotic species is the Tectona grandis. Despite the establishment of these hardwood species in plantations, wood users do not have adequate information which will encourage the maximum utilization of these species. The study was aimed at evaluating the physical which were moisture content, density the shrinkage and swelling while chemical properties were cellulose, lignin, extractives and holocellulose of coppiced teak wood and comparing to normal teak wood at the age of 15 years for its utilization. Three trees each were selected from plantations of the normal teak and the coppiced teak for the study. These trees were cut into three height portion (butt, middle and top) and wood samples selected for the test. For physical properties, 36 samples were taken from each height portion of which 18 samples each were taken along the radial direction of the stem (heartwood and sapwood). Samples for chemical analyses were taken from these samples tests of both heartwood and sapwood. These samples were replicated three times for each of the test samples. The mean values for moisture content were 49.07% and 48.73% for the normal and coppiced teak woods respectively. Density values were 842.95 kg/m 3 and 835.51 kg/m 3 respectively for normal teak wood and coppiced teak wood. Shrinkage values were 7.39% and 7.38% for coppiced and normal teak wood respectively. Coppiced teak wood swells (1.04%) more than that of the normal teak wood (0.98%). The highest density of Tectona grandis was found at the butt portion, followed by middle and top portion. Along the radial direction, it showed that the density was highest at iv sapwood followed by the heartwood. Percentage of moisture content increased from butt to top portion. Tree portion did not affect the lignin content, cellulose content, holocellulose and hemicellulose contents. From the study, the normal teak wood was proven to be better than coppiced teak wood in terms of both physical and chemical properties, but the coppiced teak wood can be utilized, in some respect, as a suitable substitute to the normal teak wood.

KNUST