Effect of air drying, solar-assisted drying and sticker thickness on mahogany (Khaya senegalensis)wood

This study was conducted at Elfaid Um Abdalla sawmill in Southern Kordofan State to improve Mahogany timber quality. Six and quarter cm thickness lumber boards of 21 0 cm length were prepared and stacked using three sizes of stickers (2.5, 3.75 and 5 cm thickness) and replicated three times for each sticker under shade or under direct sun light. This was done to determine the effect of stickers and shading on drying rate and magnitude of defects that occurred during the drying process. Moisture loss was recorded every two days by weighting sample boards inserted in the side of each stack in the center of stack. The relationship between moisture content and time of drying can be estimated and explained by the second order polynomial regression equation. The study showed that there was no effect of the three kinds of stickers on moisture loss but when comparing each stickers under shade and under direct sun light the result showed that there were no significant differences between the two kinds of stickers 2.5, 3.75 cm under and out of shading but the 5 cm stickers had lost more moisture under the shade than out side the shade. The results showed that surface checks, end checks, were greater under direct sun light. While twisting was greater under shade, Bowing and Crooking were not affected by shading. Surface checks were less in 2.5 cm sticker compared to 3.75, 5 cm. While end checks were greater in 5 cm sticker than 2.5, 3.75 cm, and stickers thickness had no affect on bowing, twisting and crooking. With isolation of shading (each kind of shading every time) there were no effects of stickers kind on surface checks, twisting and crooking out shade while 5 cm sticker had end checks and bowing greater than 2.5, 3.75 cm. Under shade the stickers had no effect on end checks, bowing, twisting and crooking. However, surface checks were greater in 3.75 cm sticker and smaller in 2.5 cm sticker. The study concluded that there was no effect of stickers thickness and shading on moisture loss during the drying process. While there was effect of shading on number of defects that are caused with the drying process. The study recommends using the smallest sticker and shading to decrease defects that are caused by drying