how can I save tree
Planted tree with dirt on top of tree base. Also formed cement in circle around tree (2 ft from trunk). The tree stands near a bayou. Leaf performance irregular.
You bring up so many topics here that I hardly know where to begin. "Dirt on top of tree base..." does that mean you put dirt on top of the root ball? Not the recommended practice; this article presents the basics of planting trees: https://www.gardeningknowhow.com/ornamental/trees/tgen/how-and-when-to-plant-trees.htm
"cement circle..." does that mean a curb? which is not going to interfere with the tree; or a large flat area of cement? this is more problematic, as trees rely on their surface roots to gather air as well as minerals and water. Roots typically extend away from the tree 2 or 3 times the width of the foliage, so a narrow band of cement will not be so harmful, but a wide cement area is not so good. Even a narrow band is going to be difficult for a newly planted tree. I know, people put trees into the middle of parking lots all the time; but not all kinds of tree can take that treatment, which brings up another topic ... the kind of tree.
I hope you planted a tree adapted to wet soil conditions, as in this article: https://www.gardeningknowhow.com/ornamental/trees/tgen/wet-soil-trees.htm
You don't mention how long the tree has been planted. If it was done recently, you might be able to pull it up and replant, or plant a different tree. If it's been in awhile, you might be able to save it by removing, or at least breaking up the concrete, and scraping some of the soil off the surface around the tree. You might also think about improving the drainage in the tree's area: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/yard-drainage-problems.htm