Question
At our Early Learning Centre we have a 14 year old weepng mulberry tree in the playground.  The tree was growing on a lean, and last year it split during a storm.  When the tree was dormant it was removed from the hole, replanted, pruned and straightened.  We have kept it secured in a straight position all year.  The tree is now dormant again, however I notice a 8inch split at the base of the trunk and approx. 2inches deep into the tree.  Fungi is growing in the hole.  The tree does not seem very secure in the ground when I shake the trunk. The rest of the tree does appear healthy and new buds are beginnining to shoot. We would really like to save this tree, as it has sentimental relevance to our Child Care Centre as well as being a beautiful tree.  We hope you can advise us how to save the tree.
Thanks,  Kathy

Answer
It is more than likely not as stable as it will get---the root system  has not had enough time to grow out  of the planting hole enough to stabilize it fully.  Sounds like a decay fungi has entered the woody cells of the tree trunk. When a tree has a injury to the bark decay fungi spores can infect the wound and over time will decay the woody inter part of a tree. Maples a thin bark and can be wounded easily. The trees living cells are just under the bark and the cells making up the wood are dead. The decay fungi will not kill the tree but over many many years could weaken the trunk. Since the tree is large I doubt the fungi will weaken the trunk to cause any concern. The mushrooms are the fruiting bodies of the fungi that is living in the tree. IF the leaves are green and the foliage if full the tree is ok. I would recommend that you fertilize the tree with 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. Apply the fertilizer just before  a rain storm and you will not need to water it in.  
I would let the tree grow and the fertilizer should increase the overall health of the tree. You will be able to tell after it leafs out fully. But I would expect the tree not to have a full foliage due to the stress of the move. I think it will be fine.