Milling a walnut with crack across the trunk

[NH4000]

Hello,
I am new to this site and think it will be my best place for information on chainsaw milling. I had a walnut tree taken down a few days ago and hope to get some decent lumber out of it.

My problem is that the tree appears to have a crack through both trunks straight across the log. Should I be milling parallel to the crack, and write off the center board or two of each log or perpendicular to the crack, settling for narrower boards.

It seems to be all the way through the length of the tree.

The pictures were taken within a couple of hours of cutting and I have applied anchoseal to all the ends. The logs were lowered with a crane. The cracks appear to be in the tree all along.
   
https://forestryforum.com/gallery/displayimage.php?pid=146073#top_display_media

https://forestryforum.com/gallery/displayimage.php?pid=146074#top_display_media

https://forestryforum.com/gallery/displayimage.php?pid=146075#top_display_media

Also, should I leave the sapwood on or square off the cant?

I left the links in for the photos in case the images are too small.

Thanks in advance
Steve

[T Welsh]

NH4000, This is typical with fresh cut Walnut,it is purely a surface check and that,s all, I see no evidence that it goes straight through the log! On how to cut it,that's totally up to you and what you would like to get out of them. I flat saw all my walnut and do not cut the sap wood off. The sap wood can always be trimmed off after drying if desired,it just gives you more options. Tim

[NH4000]

Thanks Tim,

By surface check, do you mean that only goes into the log a couple of inches?

The reason I thought it went through the log is that the same check is on both ends of each log, and is aligned. I didn't think a check would form so quickly after cutting.

Another consideration for milling is that being a two trunk tree, will the slight lean of each trunk affect the straightness of the boards?

Steve

[Ianab]

Another consideration for milling is that being a two trunk tree, will the slight lean of each trunk affect the straightness of the boards?

Possibly, but 2 things make me think you need not worry too much in this case.

Walnut is a pretty stable wood, and the pith is not badly off centre in the end of the log. If a tree grows under serious stress (a heavy lean) the pith and heart wood will be out of centre in the log. That's a bad sign.

Ian

[NH4000]

Hi Ian,

Photo #2 is not badly off center?

What is the best way to mill when the pith is off center?

Thx
Steve

[beenthere]

Steve
Welcome to the Forestry Forum.

Am thinking the same as other responses, and bottom line is you don't need to worry about the visible check. You 've done good with the Anchorseal and can move forward and cut the logs any way you want.

The check is just some growth stress-relief that happens when sawing across the log. 

The off center pith may or may not have an end effect be it some bowing or crooking of a board. But not something that would take away from the grain figure in the end product. May even add to the figure and be desirable.

Thanks for the pics.

[Chuck White]

Welcome to the Forestry Forum, Steve!

[Ianab]

Hi Ian,

Photo #2 is not badly off center?

What is the best way to mill when the pith is off center?

Thx
Steve

Not TOO badly. It is off centre, but I don't think it's enough to fret over.

Try and keep the rings even across the boards. So maybe start with the wide growth rings vertical? It's when you get different stresses in the same board that weird things happen. A bit of bowing or side bend you can usually control or rip out later after drying. Twisting makes things difficult.

Ian

[dboyt]

Welcome the forum!  If the rings are not off-center, I saw the cant parallel to the crack so that the defect is in as few boards as possible.  The off-center log shown in your photo isn't too bad, considering it is walnut, which is pretty stable.  The side of the log where the rings are further apart is the "Tension wood", which has a different cell structure from normal wood,and tends to shrink more, which warps the board while it is drying.  As much as possible, I mill the log so that tension wood and normal wood are not mixed in the same boards. I hope this diagram makes sense.



 

Here is a more extreme off-center log (Osage orange).  It seems to be air drying fairly well, so far.



 

[Magicman]

First, Welcome to the Forestry Forum.   

You stated that the check was on both ends of the logs, so saw parallel to the check unless you want narrow boards.  Check is common in Walnut and especially in Cherry. 

Your second and third pictures indicate that the tree had some lean or possibly more limbs on one side.

[NH4000]

Thanks,

The two trunks were at a pretty narrow angle but the branches mostly grew away from the center of the tree until the very top.

[NH4000]

Followup post:

Just cut into my first log. To all those that said not to worry too much, you were right.

The checks go in 3-4" and stop. My first log I tried to saw parallel to the check but that was not necessary. The checks were not parallel on this log so if it was through the log I would have had a big mess.

As it turns out, I sawed perpendicular to a lot of knots, so my first set of boards is knotted up the center, with some nice figure around the knots. I have to be more careful on reading and planning on the next log to maximize my grain.

Wish me luck.

Thanks

[Magicman]

Wish me luck. 

Ok, I wish you luck, but more importantly......fun.   

[NH4000]

So I milled a log this weekend with the pith off center. I was live cutting 4/4 boards and about 3 boards in the board popped and split full length.

I started my next cut from the end I had just finished on and the crack opened and followed me as I cut down the log.

Came back again in the same direction as the first crack and was OK until the saw completed the cut and POP!


I tried to cut per dboyt's diagram, with respect to the pith direction from center. I did not saw off the "cheeks" of the log since I was live sawing to save the trouble of turning the log.

Is this something that just happens or should I be milling off 3 sides of the log before going in for my boards? I put sealant on the logs and can't tell if this is growth stress, drying stress, or thermal ( the temps had just dropped and the outside of the logs could have been colder than the inside).

Any ideas?

Thanks,
Steve

[POSTON WIDEHEAD]

Thats gonna take a lot of putty.  ;D

[Magicman]

The pith check was obvious in the first couple of pictures.  You should have been sawing parallel to that check. 

Our Walnut very often has pith check and our Cherry always does.  The check usually can be seen on each end.


 
Notice that the pith check is oriented so that it is parallel to the saw through in this Cherry log.


  
It went from end to end and was contained within two boards.

[POSTON WIDEHEAD]

Good pics Lynn. Very good! 

[beenthere]

can't tell if this is growth stress, drying stress, or thermal

I'd say growth stress.
The wood laid down in the last years growth is higher in tension, and this tension can accumulate with each years' additional growth layer.

[mikeb1079]

i think beenthere is right on.  i've had that exact same thing happen to me sawing black cherry.  don't fret about it too bad, just dry the lumber and edge out the split end later....

[Magicman]

I always measure and use the toe boards so that the pith check is exactly the same distance from the sawmill bed on each end.  This minimizes waste.

[NH4000]

Thats gonna take a lot of putty.  ;D

I am going to make ironing boards for pants. :D

[POSTON WIDEHEAD]

Thats gonna take a lot of putty.  ;D

I am going to make ironing boards for pants. :D

You're killing me!!!!  :D :D :D :D :D

[NH4000]

Magicman,

From reading earlier replies, I was attempting to work around the offcenter pith, rather than the check. Would I have had this happen if I was parallel to the check in the last photo?

I am not making a 3 sided cant, so if the sapwood has a lot of tension, I could see it contributing to this. I am cutting off the sapwood later but would think it's worth the effort to get wider boards in one piece.

I would save putty too.

[Magicman]

When I am setting a log up for sawing the pith check takes priority over an off center pith.  The off center pith may give you some problems, but sawing perpendicular to the pith check will give you what you got.   :-\

The pith may be on one side of the log on one end and on the opposite side on the other end.  I give top priority to the pith check and level the center of the log, not the pith.  I then level the pith check an equal distance from the sawmill bed on each end of the log for the second face opening.

I do realize that I am talking band mill and you have a CSM.

[NH4000]

beenthere said:
I'd say growth stress.
The wood laid down in the last years growth is higher in tension, and this tension can accumulate with each years' additional growth layer.
[/quote]

That is an excellent point. I am visualizing what is going on here. When spring comes along a tree is sitting there, with its structure supporting its whole weight, just like a tower or a skyscraper. Because of this whole weight of the tree, which is tons on tons, the tree is in compression.

The weather warms up, leaves come out and start making food from the sun, and a new ring of growth is growing on the outside of the tree. All these cells are babies, so they don't have too much to do just yet. All the new growth up to weighs a lot, and all the old heartwood and the older sapwood have a higher load on them now.

The cycle continues each year unless the tree is cut down. Now there are logs with no load on them. In an hour, a log can go from supporting many tons of canopy, to laying on the ground doing nothing. Because the outer cells on the tree just grow, not supporting anything, but also not pulling on anything in tension, and the inner cells were in compression, now all that stress has to be equalized.

The center of the tree will elongate because its compressive load is gone. It is still attached to the sapwood, so the sapwood goes into tension, to equalize the stress.

I think this is why I saw checks across the trunks as soon as they were cut.

So, cutting the sides off for a 3 sided cant makes perfect sense, because it would take the tension wood off the compressed core and let it relax. Other than that, how would you stress relieve a log? Time seems like the other option.

I know this happens in metalworking, but didn't know the source of the stress in wood. Thanks for making me think about this.

Steve