Tension in dry logs?

[broker farmer]

How long does it take for logs to dry out if stored in a dry location?  Will dry logs still have tension within them?

[mike_van]

Not sure about tension, but i'm sure there will be some.  Biggest trouble I see with drying logs is they will check to the heart on at least one side. Also bugs? If they are not de-barked? 

[Coon]

There is definately still tension in some dry logs although some of the tension is lost during drying.  I do saw some dry white spruce at times and do see alittle tension where I would normally see alot had the log been green..  Lumber does not tend to pull as much if the log is dry but I do find that the strength of the board is not the same as if it were cut green and then dried. 

If you are going to have logs sitting for a lengthy period of time before sawing use of anchor seal will definately be beneficial in preventing checking of the logs.  Logs can and should be peeled and stacked off the ground if they are going to be dried before sawn into lumber to prevent bugs from lowering the grade of the logs hence lowering the grade of lumber. 

Planing of lumber cut from dried logs can also be problematic.  Often the lumber is too dry and when ran through a planer tearing of wood fibers is caused thus again lowering the grade of lumber.  To achieve a planed effect from these types of lumber I often run it through a thickness sander instead.
:D Brad.  ;D

[Bibbyman]

Just my opinion, but I don't think letting logs dry will help the tension situation at all – unless you let them go so long they're only good for firewood.  

In fact,  I'll say it'll make things worse.  As mike-van stated,  the logs will start to crack and then when they're sawed,  the tension in the wood will cause the cracks to open up even further.  I've sawn walnut logs that have started to crack and as soon as the first slab is cut off,  they popped open like a ripe water melon.  

[Coon]

Yes as Bibbyman stated that the cracks often do open up more when sawing dry lumber. When I say tension in logs I mean the the twisting and warping right off the saw.  I had thought that I better clear that up before one misinterprets what I previously said. :D
Brad.

[bull]

off the saw / you have that right, I have had spruce and fur down for 2 or three years walk right off the mill half way thru a 10 foot cut. Pretty scary!!

[Tony_T]

There is definately still tension in some dry logs although some of the tension is lost during drying.  I do saw some dry white spruce at times and do see alittle tension where I would normally see alot had the log been green.. 

:D Brad.  ;D

Just a quick correction.  Conifers (spruce) have compression wood and hardwoods have tension wood.  That is the stress is on different sides of the log for hard vs soft woods.

[Tom]

There is a difference in "tension" when sawing and "tension wood" or "Compression Wood" when describing the physical attributes of the wood.   I think that tension can be used to accurately describe the movement of wood as lumber is removed from the cant.

Your definitions are correct though and are worthy of note.

[pigman]

There is a difference in "tension" when sawing and "tension wood"

I have a lot of tension when a customer wants straight 2 X 4s out of small hickorys. :'(