Warping of Boards Cut from a Dead Standing Tree
Uneven drying stresses in standing dead wood may cause warping after the log is sawn. March 3, 2006
Question
Last spring I chose two pine trees to saw up into 4/4. One 18'' green and one 24'' dry tree (had died last fall). The lengths were 8' 6'' sections with no knots. After sawing on my bandsaw mill, I stacked and stickered in an enclosed shed to dry through the summer. Last weekend I pulled the boards to plane for a flooring project and found that the green boards were nice and straight, but the boards from the dead tree had a lot more warp and cup. The dead wood was stacked on the bottom side with more weight to secure it, while the green wood was on top in the stack. Why the difference? It seems to me that it would have been the opposite. The dead wood was wider than the green. Green was 6 to 8 inches and the dead was 8 to 12 inches.
Forum Responses
(Sawing and Drying Forum)
From contributor J:
Did they grow in the same place? Was one leaning and the other straight up? What does the grain look like - spiral, sloped? Did you saw them the same way?
From the original questioner:
Both trees were sawn the same. The dry one was cut approximately 12 hours later - the next morning, to be exact. The trees were pretty straight, and about 200 feet apart when cut off the stump. The grain was more sloped, not spiraled at all. I do not recall the temp or humidity of both days. Does this help?
From contributor L:
It has to do with the fact that the standing dead tree had already been drying for a year or more in the round. This would have caused a great deal of internal stress as the outer layers dried ahead of the core of the tree. Then when you sliced it, part of the board was dry and part was less dry. It would be nearly impossible to predict the outcome. Quartering the log would have produced better results.
From the original questioner:
Thanks. I guess that you recommend not cutting dead logs on the stump when air drying. Is there a way to make this possible, or would you just have to use this type of wood for utility jobs? I do appreciate your comments!
From contributor T:
Could it be that the wider boards that warped were cut from the center cant, through the heart? This would cause uneven stresses and cupping. Usually, pine is fairly forgiving.
