Drying Tree Disks Simply and Without Defects

The presence of boxed pith in tree cross sections creates differential shrinkage stresses during drying which, combined with even small surface stresses, will cause checking in the form of V-shaped cracks. The disadvantages of chemical stabilizing agents such as PEG include long treating times and discoloration of the wood. Disks dry with fewest defects if they are small in diameter, thin, and cut obliquely to the stem axis. A simple method for drying tree sections is outlined in three phases: the inner section of the disk is covered with plastic film to prevent heart checks while the sapwood, exposed to the air, dries rapidly from green to 30 percent moisture content; the plastic film is removed and the entire disk dries at a moderate rate to 25 percent moisture content; in the last stage, the disk is placed in a plastic bag with small holes and dries slowly at a decreasing rate for about four weeks to prevent surface checks and V-cracks as it reaches its final moisture content.

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