Then in some cases depending on the weather and where your tree is located, it may be under stress.  A sign of tree stress is a very thinned out tree which has had very little growth over the years, dead wood, surface roots on the lawn, small leaves with light pigments.
 
This tree is a very good example of a tree under stress.  Notice how thin it appears, with small leaves.  This tree is a of drought and desperately needs to be set up with a spring / full deep root plan.
Tree Care Management offers a state of the art deep-root feeding plan which injects under high pressure injects the ground with highly enriched nitrogen,, and specially designed to stick to the soil in proper ground zone where the proper feeding roots are.