Evaluation the effect of kiln schedule on warp and surface checking in beech (fagus orientalis Lipsky) at 5 cm thickness

In this research , beech (fagus orientalis Lipsky ) lumbers at 5 cm thickness wereran domically selected and commercially cut down from sari region(Neka choobcompany) ,with three schedule namely T5-C3, T5-C4, T6-C4 were adapted fordrying the lumbers down to the final moisture content of 8% to evaluation theeffect of kiln schedule on warp and surface checking . primary dry bulbtemperature each three schedules was adjusted at 49 °C and the final dry bulbtemperatures was adjusted at 71, 71and 82°C respectively. Basic Specific gravityand dry specific gravity were measured 0.52 and 0.61 respectively. Longitudinal,radial, tangential and volumetric shrinkage were measured 0.46 %, 5.8%,10.2%, 16.46% respectively. Quantity of defect s including crook, bow, twistand three longest surface checks of the lumber were measured before and afterthe drying process in each stage. In order to analysis the lumber defects forestimating the best schedule, quality control graph were used. In the end, resultsof investigation indicated that drying of beech lumber by using of the threeschedules was desired. However the third schedule (T6-C4) had better dryingcharacteristics than the other schedules.