After the move, the tree gradually lost all of its leaves and most of the branches turned black and are totally dead. Now within the last week, new growth is coming out near the base of the trunk up about 12 inches with the rest of the tree looking totally dead.

I'm guessing the roots have taken hold and the tree is alive. My question is where to go from here?
If the top of the tree is dead, do I need to top it or do I leave it as is until next sprIng?
For the record, I am in south Louisiana.

I cut it back to the green wood. It is still about a season behind its sister that handled the transplant without dieback. It quickly established a new leader and you can't see the cut mark unless you know what you're looking for. (This tree appeared 100% dead for a while).

In my case, moving two BCs, one was a very clean, easy relocation. The other (I assume) experienced the dieback because I got in too big of a hurry when digging it out and popped the main root. (I moved them in winter and still nearly killed this one)

I would wait for an expert to tell ya for sure. I'd like to hear what he/she has to say myself.

ken

unless it was a grafted cultivar.. in which case.. the understock is probably just the species ..

ken

Here is a Thuja plicata seedling I potted up last year. Over the winter, it went completely brown, and this spring it looked like a dead stick.
I was about to throw it away when I noticed a couple of small green shoots about halfway up the stick. I cut it back to where the shoots were, and it's starting to fill in more now.