A friend has a magnolia which has 4 branches just above the ground(i.e a short main trunk). On one branch the bark has split exposing the wood. Now more bark is showing signs of rotting around the gash which is approx 12 in by 6inches. The owner wants me to "concrete" over the scar claiming that this is what the US Forestry commission does!! Any ideas on what should be done. My feeling is that the tree is getting ready to drop the branch .The tree is over 30 years old