My oak tree has less college each year. More of the branches die each year and the leaves in the spring come out yellow. In about 3 weeks the leaves turn brown on the edges and start to fall. What can I do?? Does the tree need to be removed. Would I be able to replace it with another oak if we do need to remove it? The tree is about 17 years old and I am heart broken. This is the third year this has gone on. The tree looks worse each year . This year is the worst so far. We have give the tree cheleted iron. It did not help. Please help