Thanks all for your responses.  My poor silver maple has been getting all the wrong attention.  She is exposed to full sun from about noon until sunset.  No shade from other trees.  Plus I have been relying on my grass sprinkler watering to service the watering needs of the tree.  Big mistake!  In an effort to save the tree, I have set up a watering system independent/and in addition to the grass sprinklers.  Currently set for every other day for 15 minutes.  Just wondering if I should set the new system to daily watering?   Advice appreciated.