What can I do to let go my ash tree? There are leaves on the tree but it is not full resembling it used to be.?
Answers: Check for Emerald Ash Borers. http://www.ars.usda.gov/is/AR/archive/fe...
They are an invasive species and have decimate the ash forests in Michigan and elsewhere. If you find ash borers, contact your county on the double. They will know what to do.
My answer of course depending on the echelon of your tree is to prune it. Normally a well pruned tree is more stunning than one that grows on its own. Trim off any motionless branches or sickly looking areas and perhaps buy a purse of tree fertilizer spikes( read the label as they are species specific) and put more or less three around a large tree or one for a unbelievably small tree. Also, check out the link from the other answer contributor, bottle green ash borers are serious business. If you also have any fungus or sponging vines growing on your tree you may try to spray it with some fungucide or herbicide to take rid of those, as they seriously affect the trees health.