Stability of wood

They will tend to split from the edge in towards the centre.
Dunno about curl & twist.
I'd think blocks made up of smaller sections would be more stable, say 2" square, wher each square is quarter sawn. The prob occurs when any piece has the centre of the tree in it or rings which turn through more than about 90 degrees, although even a half log is more stable than a round log.
Del

I, too, have the experience of Del; cupping, curling, and splitting with softwoods in my native Montana. I had pretty good luck with cutting an oval shape (think of Julienne cut green beans). This technique seemed to reduce considerably all the undesired effects described.

If you need rounds with cross-grain effect, perhaps julienne, then round out (after drying) with bandsaw?

I'm reaching the point where I think it is not possible to guarantee stability in wood, no matter how it's cut. There are too many variables in wood to predict the outcome. So far, I've found that making something out of wood is a trial and error exercise. It might turn out alright, or it may warp and be totally un-usable.

Hi Ronseto,

My experience is, in most species, quarter sawn performs best overall.

Proper drying techniques can also improve stability to some extent.

Cutting "rounds" tend to split (as noted by the above commentators)

Quarter sawn also produces the lowest yields

Presumably the thing to do would be to cut a slice, then cut it into quarters let them season, square up each section and the reassemble into a round which would now be slightly smaller.
Del

Ditto to Del and others that a slice in the round will split from the edge and make a big empty jag in the round.

Some types of wood are more prone to split than others. For most species, if you dry the wood as an uncut log with the bark on, you can get good rounds from it after it has dried, and they will be stable. You may lose the ends due to splitting but the rest will be okay.

The professional drying technique (which I've never done) involves sealing the ends of the log with wax, and letting it lie in a cool dry place, bark on, for a season. If this is done right, you don't lose any of it.

I learned that you should use wood only from the trunk. All branch wood has stresses from years of resisting the torque from the off center weight. That wood will always crack as that internal stress is relieved.

It seems a waste to harvest only the trunk, but that is where the best wood is. Avoid cuts near major branches.

Thank you all for your responses. By tapping into the world of knowledge, it makes me a smarter person. Thanks also to CR4 for allowing people to get together here and share our knowledge.