Use of glass transition temperature for stabilization of board's cracks of Eucalyptus grandis.

The Eucalyptus grandis logs temperatures were determined and correlated with the board's cracks during steaming. Thermocouples were inserted in the logs center, registering their temperatures during steaming at 90°C. The logs were sawed and the board's cracks measured. It was concluded that: (1) the logistic S-shaped curve explains the logs temperature variation; (2) the logs with diameter of 20 to <25, 25 to <30 and 30 to <35 cm presented, respectively, 84.2°C, 73.1°C and 45.8°C in the steaming; and (3) the cracks lengths significantly decreased in logs that reached the glass transition temperature.