Control of discoloration in pitch pine

Specific drying conditions for control of discoloration in pitch pine were analyzed and evaluated to determine best drying temperature and moisture content (MC) to maximize high value-added uses. High-temperature kiln-drying with restraint effectively reduced twist but also caused an excessive darkening stain. Further experiments showed that this stain generation is controlled by drying at conditions exceeding 100 °C dry-bulb only until before wood core temperature reached 100 °C. Results also showed accurate control of MC and finishing the drying process at the most suitable time to be important. Boards of excellent color were produced by applying a newly developed reducing temperature drying schedule for stain control. It is anticipated that higher additional value can be obtained from pitch pine, with continued studies on stain control, resin exudation, and twist restraint.