Question
I live in the greater Atlanta area of Georgia where we had a severe drought last summer (2008).  I have a variety of trees in the front and backyards and noticed by the end of last summer the trees in the front looked "sick" having a variety of brown, yellow and green leaves.  The trees in the front include oak, dogwood and cherry.  The cherry was in worst shape with the center branches seemingly dead with healthier green branches on the perimeter so I had it removed after being counseled that "fruit named" trees simply don't live that long.  As spring 2009 approached it was obvious the remaining oak and dogwoods were not healthy, having a mix of brown, yellow and green leaves.  The oak sheds it's dead leaves constantly which is not only unsightly but a nusance to my neighbor.  He has a similar oak that looks perfectly healthy.  Whatever the issue it is isolated to the trees in front yard.

Answer
The drought in the South has injured the hardwood trees and some of the effect of this damage was delayed until this spring. The oaks and dogwood should recover. I would fertilize them with 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. You can do this just before a good rain storm and will not have to water it in. I would fertilize now and again in the spring. The fertilizer now will help strengthen the root system and the Spring will help the foliage green up.

Cherry tree were hit hard by the drought. It seemed to stress them more and several fungi were able to infect the trees causing damage and/ or death. We here in Alabama had the same drought conditions and the cherry trees most did not recover. The oaks however are looking better even though they had a less dense amount of leaves this year.

With the fertilizer and normal rainfall the trees should be ok next year.