Approximately 75% of a tree’s root system is in the top 18 inches of soil. That is amazing. The roots of a tree can extend horizontally 3 times the distance of the drip line.

Trees exposed to high winds are less able to withstand having their roots cut. Pruning roots close to the trunk does more harm to a tree than cutting smaller, more distant roots.

They also store carbohydrates. This article has additional information, Tree Root Systems. To plant around exposed roots, use small plants at first that can develop in the spaces between the roots.

A maple tree is clearly very different from a moss, yet over a long period of time, and step by step, early moss-like plants evolved to trees, including maples. The fossil record tells us about ...

It won't be easy, since the root systems are pretty tenacious, unless the tree died due to root rot. Do look at the roots when you dig it up to see if there were any drainage problems.