| Abstract:
In order to establish a kiln drying schedule for Iranian Beech (Fagus orientalis) Wood, commercially cut lumbers with the thickness of 5. 5 cm, were selected from Shast-Kola region, Gorgan. Then, lumber were dried under the kiln schedule based on diffusion theory (from Malmquist's relations) to the final moisture content of 12± 2%. This schedule was adopted and implemented for three kiln loads with three different initial moisture contents, 66. 6, 58 and 45 percent. Initial drying bulb temperature (first step) and wet-bulb temperature were calculated, respectively, at 46 ° C and 45 ° C for all three schedules. The severity of surface checks, end checks and warp (bowing, crooking, twisting) in the lumbers were measured before and after the drying process. Quality control methods were employed to analyze the wood defects. Results showed that kiln drying of beech wood based on diffusion theory was satisfactory and the severity of changes in defect were statistically acceptable in all loads. Superior characteristics of this method, was related to nearly zero surface checks in samples, because the moisture content was reduced slowly.
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