Hey Mike; I suggest leaving them round. Peel the bark green and choose if you are treating them. They are a harder
wood than most, so they last for 5-10 years in easy locations (no cows pushing on them).
Around here most folks soak them in motor oil and diesel fuel mix. Not very
Permie like but makes them last longer.
I've only seen larger cedar logs split down for posts. Even they rot, if they are not old growth heart wood.
(EDIT) Cut that lower stuff into
firewood and let it season.