DRYING OF PLANTATION-GROWN <em>TECTONA</em> <em>GRANDIS</em> WOOD WITH DAILY-CONTROLLED DRYING RATE SCHEDULES

Abstract

The study compared drying speed between schedules rather than reducing drying time, by employing high daily drying rate (DR_daily) for Tectona grandis wood. The moisture content (MC), drying defects (twists, bows, cups, crooks, checks and splits), drying tensions and colour changes were evaluated. Results showed that it was possible to dry wood in 88 hours by employing drying schedules with a high DR_daily with no significant variability in the final MC of the dried-lumber. Utilisation of such schedules increased the incidence and magnitude of twist, crook, bow and split defects, while decreased in cup and check defects. However, it was possible to obtain a lower incidence of drying defects by using an endless screw for daily adjustment of the lumber piles during drying. Drying tensions decreased with drying schedules with a high DR_daily, but slightly increased when endless screws were used. Finally, application of drying schedules with high DRdaily produced variation in the colour of the lumber, yielding more reddish (a*) and yellowish (b*) wood.