Question
We have 2 tall Christmas trees at our home in San Antonio Texas, they are almost 10 years old, about 20 feet tall. there was a accidentally fire a week ago and caught one of the trees, it burned mid way up the inside and the top of the tree, the weather and the tree were dry. I am not sure what I should do to save it; let nature take its course and leave the tree alone or trim it or heavily mulch the bottom or wash off all the dead and dying debris.

Answer
I would water it with 1 inch of water--place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. Do this every third day until it rains. No need to do anything with the branches right now. Some may live so I would let it be as is now and if there is not new growth in about a month then you can prune off the dead limbs. New ones will not grow back so expect that the tree will have bare trunk where the fire killed the limbs. I would nor worry with the mulch  for this large a tree--the roots should be ok from the fire.