When using natural trees, what would last the longest before it rots down?
I can get just about any kind of tree that grows in NC or SC. I've heard that honey locust will last a long time but the thorns would be a problen during the drop/construction/cut phase of the instalation

I'll be dropping these in 10 to 30' of water if that matters.

Just want these piles to last more than 2 years, witch is all that a Christmas tree will last. (frasier fir)

Any help would be apriciated