I recently agreed to re-dry a T/L of 4/4 old growth quarter sawn walnut. How old it is I'm not quite sure. It was large timber. Upon arrival into our yard, we verified MC ranging from dry 7% to 68% (oven testing). Keep in mind this lumber had already gone through a 20 day drying cycle using a T6-D4 schedule. In my 34 years of experience, I would never had believed this without seeing it myself. 30% of the boards in this load varied in MC and within the same board. Using a pin meter you could get a reading at 7% and 2" away, get a reading that was 60%, then 4'' down the board, it would read 12%. We did re-dry this, although since we had to go into equalization right away, it took another 27 days to bring this all within 6-8%. I'm aware that quartered lumber will take longer to dry, but my past experience would tell me that I would have to add days, not weeks. I'd never seen anything like this until our last kiln charge ?again, wet pockets. This also is only showing up in the quartered material. Do you have any idea what's going on? It's almost like the moisture is being blocked in certain areas of the board, not being allowed to escape through the edges of the boards.
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
You have described bacterially infected wood. The result of such wood is wet pockets that are just as you described. It is most commonly seen in q-sawn wood. The basic prevention technique is to use adequate kiln samples and then double check the final MC of up to 30 samples with a moisture meter.