Fine Tuning Equalizing and Conditioning
If lumber is not properly equalized and conditioned during drying, problems will surface during further manufacturing and end use. These problems range from bad glue joints, to stair stepping1 in panels, to twist, cup and warp of finished panels, to splitting of panels.
The link address is: http://www.ces.ncsu.edu/nreos/wood/wpn/finetune.htm