Pro Ligno (Jun 2015)
ASSESSMENT OF DIMENSIONAL STABILITY OF GMELINA ARBOREA WOOD USING MODIFIED GREEN HOUSE DRYER
Abstract
The dimensional stability of Gmelina arborea wood was investigated using the modified greenhouse dryer. Daily temperature and relative humidity patterns in the Greenhouse and air-dry shed were assessed to determine their influence on the moisture variation, density, volumetric shrinkage and volumetric swelling of Gmelina arborea after drying for 40 days. Wood samples were obtained from a twenty-year old plantation at the Federal University of Technology, Akure. For laboratory work, 45 freshly cut samples of 20mm x 20mm x 60mm were dried in the oven at 105⁰C for 24 hours until they attained constant weight while for field experiment, 45 freshly cut samples of 25mm x 75mm x 450mm Gmelina arborea wood were loaded into the Greenhouse dryer and air-dry shed respectively. The result obtained for average daily temperature and relative humidity pattern in the greenhouse for the period was 31.17⁰C and 77.29% respectively while 22.47⁰C and 84.57% were recorded for air drying shed. The attainable moisture content for Green house dryer after 40 days of drying was found to be 19.05% while air-dry medium was 31.46% which showed that greenhouse medium dried the wood below fibre saturation point, a better performance over air drying method. Wood samples of Gmelina arborea in the Greenhouse dryer were found to be more stable in terms of swelling and shrinkage attained. The result of the overall mean density for Gmelina arborea wood was found to be 463.89kg/m3 which classified the wood as non-refractory because of its low density
