Question
The bark on my 27 year old fruitless mulberry tree is falling off.  A long crack first appears and then the bark starts falling off.  My neibor trimmed the tree last year and this year the bark started to fall off.  The other tree which is 15 feet away seems fine.  Will I lose the entire tree? And What is it?  thanks for any help you can give me as I live in Las Vegas and the shade from these two trees are very helpfull.

Answer
Anytime the bark comes off a tree trunk is not a good sign.  The pruning did not cause the problem.  If the tree has branches that die from the tips back into the main crown, then the tree has dieback and is under great stress.  There are no cures for this problem.  If the bark comes off all the way around the circumference of the tree, then it will die.  All you can do is watch and wait at this point.  A some point in the future the tree may have to be cut down.  The tree may live several years with this condition.  It is not contagious, so it will not spread to the other tree.  The tree may have been struck by lightning at some time in the past.