Maple tree can developer circling roots, especially if planted too deep.  What happens is the roots grow in a circular pattern and eventually choke off the tree.  Another cause of girdling is if rabbits or mice chew the bark of the tree all around limiting the amount of water and nutrients available to the tree.  I can’t tell from the picture whether or not this may be the case.

Pull back the turf and look for roots that circle. Another test is if the trunk moves a lot when shaken.  The following websites will give you pictures of what to look for and what do to about it in the future.

1. https://www.swnewsmedia.com/chanhassen_villager/news/the-root-of-the-issue-with-maples/article_df<personal data hidden>-5381-bbcb-31ce1e2ab223.html

2. https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/environmental/girdling.

3.  https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/maple/leavesbrown.html

It was beautiful.  A suggestion for the future: Mulching around a tree without letting the mulch touch the bark helps tree so they don’t have to compete with grass for nutrients and water. It also protects from injury from mower blades.  Thanks for sharing the picture.