If you are concerned with what you see covering your fence post they are called incisions and they have very little effect on structural integrity so as that goes if that's your only concern don't worry about it unless you see the actual wood rot at the base etc, if that's the case replace the post.

Not often do you come across wood with incisions nowadays, usually, you see this on pine wood but very rarely.

Good luck

Yep, probably a piece that should have been culled out at installation time, but fence company installers typically install what they are given without extras to allow for that.

I did not see any email notifications. So, I’m just now seeing the replies.

I can break pieces off in that area with my fingers. So, I thought it might be some kind of wood rot or termites that would eventually spread and affect the structure.

If it’s only cosmetic, is there any cosmetic fix such as putting some kind of coating or sealng over it to prevent the splintering?

" f it’s only cosmetic, is there any cosmetic fix such as putting some kind of coating or sealng over it to prevent the splintering? "

No. Ike I said should have been culled out before installation. Only fix is replacement and that will be up to you as there is nothing structurally wrong with that post at the moment. It may rot faster than the others but then again it may not. Just not as pretty.

I looked up “incisions” and those are the holes in the wood.

That’s not my concern.

I’m referring to the wood breaking off from the edge in the photos.

I know, that is from the "incisions" and most likely some wane on that edge that that is happening.