REDUCING MOISTURE-CONTENT VARIABILITY IN KILN-DRIED HEM-FIR LUMBER THROUGH SORTING - A SIMULATION

For 5 of the hem-fir species plus mountain hem-lock, a drying curve wa s determined for each of 33 boards dried according to the same kiln sc hedule. Despite large differences in initial moisture content (MC), va riability in final MC between species was small relative to the board- to-board variability within each species. The drying curves were used in a computer simulation to investigate alternatives to using a long e qualization period to obtain moisture uniformity. Results of the simul ation indicate that presorting by green density does little to reduce moisture variability. Postsorting by MC can reduce time in the kiln by 10 percent and decrease board-to-board MC variability.