KILN DRYING OF ACACIA MANGIUM WOOD: COLOUR, SHRINKAGE, WARP, SPLIT AND CHECK IN DRIED LUMBER

TENORIO C, MOYA R & QUESADA-PINEDA HJ. 2012. Kiln drying of Acacia mangium wood: colour, shrinkage, warp, split and check in dried lumber. Acacia mangium is one of the most planted species in tropical countries. However, dried lumber has been limited by high presence of warping, splitting or checking and lack of uniformity in the final moisture content and wood colour. The aim of this research was to investigate the cause of this situation after drying. Climatic conditions where trees grew, height of the tree, grain pattern, drying schedules, distance from pith and heartwood presence were recorded. Initial and final moisture contents, heartwood percentage and shrinkage percentage of board, warp, split and check were also measured. Results showed that colour change of dried lumber was affected by drying schedules and climatic conditions. Width shrinkage percentage of wood was affected by final moisture content, climate, radial wood percentage and relative distance from the pith. Shrinkage percentage of board thickness was correlated with specific gravity, relative distance from the pith and drying schedule. The incidence of boards with twist, bow, split and check increased after drying. Crook and twist have the highest incidence rate. The quality parameters of these boards were affected by climate, grain pattern, initial and final moisture contents and drying schedule. The control of variables with effects on final moisture content, warp and wood colour improved the quality of lumber after drying process.