A study on the effects of grain orientation on the quality of kiln dried poplar lumbers

Poplar lumbers with nominal thickness of 5 cm from Taleghan region، located in west of Karaj were dried under three different schedules، including T8-F4 (recommended schedule by F. P. L for poplar)، T8-F5 and T9-F4. Dry bulb temperatures for the schedules were adjusted at 54، 54 and 60 °C، while the final temperatures were 82، 82 and 71 °C، respectively. The severity of warping، honeycombing and surface checking in kiln dried lumbers were measured and analyzed. Results showed that flat-sawn boards dried faster than quarter-sawn boards. The grain orientation had no effect on the occurrence of warp، whereas cracking largely occurred in flat-sawn lumbers.