I have a very large, very old (50-60 years) elm tree that lost a significant branch in October 2000 when we had snow while the leaves were still on. The branch split from the main trunk and left a 2-3 foot slash-like wound in the side, about 20 feet or more up the trunk. It seemed to heal, and the canopy and branches seem ok. However, I noticed a large black shelf-like fungal growth last winter. It is now larger, and creamy in color. There appear to be 2-3 'shelves' and they are larger than before. Is there anything to be done? Will this invasion kill the tree? (Sorry - I initally posted this under Bulbs accidentally...)