Photographs and SEM studies the structural changes in boards with different drying method shown in Figs. 4–7. The photographs shown in Fig. 4a-4d of cross-sectional area at a) 50C, b)60C, c)80C and d)100C by convection drying.As seen, a large cavity appears in the inner section of these samples, depending on the temperature increases, implying that the board samples were puffed.