I think my tree is dying. The leaves were very sparse and small this year. Some of the branches have bumps which look like raised cankers – similar to a human’s boil or mole. They are ugly. The tree is about 25-30 years old. It used to be beautiful. We did not cut it back this last season. Can I save this or has something gotten a hold of it?
Cankers are generally caused by a fungus.
The effected branches should be pruned off and disposed of.
This can kill a tree by girdling the tree.
You may want to have a professional examine the tree.
Here are some links for you.