Mature red maple dying
We have a 20-25 year old red maple growing in full sun. It began showing isolated dying branches summer, 2014. This summer, 2015, the condition has deteriorated noticeably. We do not see any pests nor discoloration on healthy leaves, but leaves and seed pods yellow and wilt on the dying branches. (see photos). We have not applied any pesticides or fertilizers.
Your maple tree may be suffering from a rather common fungal disease known as cytospora, but we see no definitive signs of that or other disease in your photos. The wilting and yellowing may simply be the result of scorch.
The best strategy for you to pursue is to prune out the obviously dead wood and provide the tree with supplemental irrigation during dry periods. All plants would like to receive 1" of rainwater per week, so if rainfall is inadequate, place a garden hose under the tree and allow it to trickle for an hour or so each week.