Model predicted and CT scanned moisture distribution in aPinus radiata board during drying

Abstract

Pinus radiata sapwood boards of 100 × 40 × 1200 mm were dried in a tube dryer at Lulea University, using a computer tomography (CT) scanner to scan the wood during drying. The CT-scanned wet wood density can illustrate moisture distribution within wood when the wood basic density profile is known. The CT-scanned results were used to validate a 2-D single board drying model developed at the New Zealand Forest Research Institute. The validation has shown that the model is not only capable of predicting the average moisture content but also moisture content gradients in board thickness, width and within growth rings. To investigate the effects of sawing pattern and intrinsic wood properties on drying, the input parameters for the model include within-ring variations of wood density, green moisture content and wood permeability. The model can assist in understanding the causes of some drying defects and has potential for the development of drying schedules.