Preliminary observations on the utilisation and wood properties of plantation teak (Tectona grandis) and African mahogany (Khaya senegalensis) grown near Kununurra, Western Australia

Abstract

Summary The wood properties and wood quality of single trees of a 22-year-old teak (Tectona grandis L. f.) and an eight-year-old African mahogany (Khaya senegalensis A. Juss.), grown in irrigated plantations in northern Western Australia, have been assessed. Logs were cut into 25 mm backsawn boards using a thin kerf ‘Wood-mizer’ bandsaw, and the boards dried to 7 per cent moisture content in solar kilns. Basic wood properties (i.e. green density, basic density, air-dry density and shrinkage), as well as recoveries, sawing and drying behaviour and working properties (i.e. sawing, sanding, colour, planing, nailing and staining) are assessed, indicating both species show potential for value adding. Provided a large plantation resource is developed in the region, considerable potential exists for a new industry based on high value tropical timbers. Green sawn recoveries for teak and African mahogany were 56.5 per cent and 36.0 per cent respectively. The African mahogany logs were larger than the teak, but the fluted shape of the butt log reduced recovery. Teak had a mean basic density of 610 kg.m'3 and mean air-dry density of 700 kg.m−3 and African mahogany a mean basic density of 600 kg.m−3 and a mean air-dry density of 680 kg.m−3. The plantation teak is golden brown in colour with dark markings, and African mahogany a pale orange with pink streaks. Both species were glued with urea formaldehyde (‘Grasp’) by hand clamping and cold pressed for 24 hours. Both species indicated good working and staining properties. Nailing teak boards caused splitting, and drilling before nailing is recommended. In some cases, African mahogany boards may require drilling before nailing. Results indicate that the single sample of both species processed shows potential for value adding and processing of a larger sample to confirm plantation versus natural grown material comparisons is highly desirable.