My dad and I set a rail fence in 1969 around his house.Wouldn't matter much...young small diameter trees like that would not last long enough to be worth the effort to build that paddock with them. Here in NW Oregon, that is. Hand split posts from large old growth trees would last longer, but not much past 20 years.
Dryer climates, your mileage may vary .
Port Orford cedar posts.
The new owners took it down 2 years ago!!!!
What happens here is the sapwood goes to Hell fast, but the core lasts forever.
I was taking a forest fence down , all oak posts.
So I just ran the tractor over them, after we removed the fence.
Front wheel broke them all.
Except one.
That was Port Orford cedar, so it bent over, then came back up and blew the lower windscreen on the tractor out............................BAM!!
Not my proudest moment.