How is the landscape managed in your yard? Are you practicing organic methods? One common reason trees fail like this is if "weed and feed" chemical products were spread in the yard and around the tree. The packages state not to use it near trees (shouldn't use it on the planet, but that's another topic!) but people fail to read the instructions and end up poisoning trees, which are broadleaf plants (something that the "weed" part of weed and feed is targeting).
Try the entire
Sick Tree Treatment and if you did use a weed killer in the yard, consider putting out an application of
zeolite.
Even organic gardeners have had a difficult year. We had a very wet spring, so it may have been the luck of the draw for your tree in the amount of water that stood around its roots for many weeks. This stressed a lot of plants (it played havoc with my vegetable garden) and for a lot of homeowners, it'll take until next spring for their trees and plants to cycle through a dormant season before the see trees and shrubs come back at regular strength (if we have normal rainfall).