Controlling Splits in Pecan
An explanation of various causes of splitting in lumber as it dries. November 14, 2009
Question
I have a stack of pecan slabs (1" to 2" thick by 12" wide). The ends were not sealed 2 years ago when stacked and are now split - some splits are 24" long. I plan on restacking. I am concerned that the splits will continue to lengthen. Should I cut the ends to remove the splits and seal the fresh cut ends?
Forum Responses
(Sawing and Drying Forum)
From contributor J:
Why not just seal the ends as they are? I don't see what benefit you'd get from cutting the planks short.
From the original questioner:
I was thinking the splits (24" long) would be hard to seal and might cause stress to help the split grow.
From contributor J:
It's the end grain that needs to be sealed, not the inside of the split. Also, the splits occur as a way of relieving stress; they are not, in and of themselves, sources of stress.
From Professor Gene Wengert, forum technical advisor:
End coating now will do no good at all for controlling the splits. Small splits are a result of no end coating when the wood was green and started to dry. Larger splits are almost always a result of stress in the tree (called growth stress) and are not controlled by end coating. The splits now will not lengthen appreciably as drying continues to a low MC if stacked normally, as at 24" the stress has been relieved almost completely. However, if you cut the existing splits off, then you might see new and long cracks develop, even with end coating, as drying continues.
From contributor J:
Gene, could you say more about why, if the stress has already been relieved, new long cracks might develop if he trims off the existing ones?
From Professor Gene Wengert, forum technical advisor:
With a new end, there will be stresses (growth stresses) that the wood cannot hold back. With the cracked end, it takes more stress for the crack to grow. So, on a piece that is not fully dry, you have growth stresses and perhaps added drying stress (ends dry faster than the rest of the piece). I have seen a piece with a split that is trimmed and the stress caused an immediate new split. I have also seen pieces that had big splits and then when they were machine planed, the split doubled in length (stresses caused by planing added to stress in the lumber already) or even broke into two pieces.
