Releving tension in soft woods.

[Brucer]

Would you center this one where the green cross is, cut an 8x8 out of it and expect it to stay reasonably straight?
There is no noticeable sweep to the log.

I don't often see a straight Douglas-Fir with the center offset that much. When I do, it is usually at the butt end only.

It's rare to have D-Fir 8x8 move very much. If I were given a log like that to saw, I would sawn an 8x10, with the 10" dimension going from left to right. If the timber remained straight I'd take an inch off each side. If it move a lot I would saw one side straight and then the opposite side.

What Tom is referring to as a "heart check" would be called "shake" in BC. It's usually caused by wind. There is no guarantee that it will remain parallel down the length of the timber. I recently sawed a 26 inch log that a customer brought in. It had some heart shake at one end similar to what you show. Nothing was visible at the other end. But the shake spiraled through the log turning 90 degrees in 16' before fading away just at the other end. Not only did it spiral, it also moved off center.

It's very common to see other cracks opening up inside the log, all associated with shake. When I see something that small, I try to keep it inside the timber, rather than sawing smaller pieces out of the log.

[customsawyer]

What we call shake down here is a crack  between two or more growth rings. It is more of a problem in Cypress and hemlock than in the hardwoods.

[beenthere]

custromsawyer
You are correct with the "shake" and Tom with the "heart check". Some people confuse it, and call heart check by the name of "wind shake". Hasn't anything to do with wind and more to do with growth stress building in the tree as it grows.

[Magicman]

Correct.  Shake follows the growth rings.  Check splits across the growth rings.
 


Shake.

[cutterboy]

Magic, I just love it when you show us pictures to make a point. It's easier for me to understand something when I can see it.  Thank you.

[Brucer]

The Canadian Softwood Lumber Grading manual identifies two kinds of shake -- "ring shake" is a split between growth rings. "radial" or "star" shake is a split across the rings. Star shake is not the same as end checking or checks caused by drying -- it occurs while the tree is growing. This is probably one of those "local terminology" things.

Several professional log buyers in BC have told me that shake in Douglas-Fir and Western Larch is mainly caused by continuous exposure to wind. I know from bitter experience that there are certain areas in this region that produce 100% wind-shook (?) D-Firs.

D-Fir and Larch are the tallest trees in the interior forests. They don't like shade and tower above the other species. This makes for very long trunks that flex a lot in the wind. I suspect that's the reason so much shake is found in windy areas.

[ljmathias]

Just an observation of the value of the forum and staying up to date- this topic has come up multiple times in different context each time.  That helps you see how one piece of information can be used in different ways: Tom's discussion of aligning the check at 45 vs 90 degrees is a good example.  My memory (such as it isvv ) had me thinking that the 45 orientation was good for sawing everything- not true and glad to have the clarification. 

The second part of the observation has to do with the combination of explanation and pictures, and part of the reason we love pictures so much here is because that's where the information becomes real.  Someone can describe something to me and I mostly understand but show me a picture or two, and wham! It's real!  Of course, you only learn how to apply the knowledge by doing- the hands-on part with all the trial and error that comes with it makes the information into application, and that's what we're all looking for.

Sorry, guess the teacher in me just won't die completely... 

Lj