Q.Japanese Maple Tree branches dying
Starts out at tips with black discolor and works down the branch and turns white almost like snow. Help!
Tell me more about the tree. What is happening to the leaves on the tree? What percentage of branches on the tree are exhibiting this problem and what part of the tree are the branches affected?
Twig dieback on japanese maples is often bacterial in nature and if it is bacterial, immediate pruning (which can sometimes be severe depending on your tree's situation) of the infected areas is typically the recommended course and your tree can make a full recovery if this is done in a timely manner. However, twig dieback can also be attributed to many other causes (fungal diseases, insects, climate conditions, cultural practices, and soil chemistry) which makes this really hard to diagnose remotely. You may want to consider contacting a local arborist to take a look at your tree.
Here is the link for Japanese Maple problems:
Here is a link to Japanese Maple tree care and possible issues with your tree.
Could your tree have been exposed to cold temperatures? This is my first thought by your description of the damage to the tree.