Q.damaged plum tree
My new plum tree was skinned with a weed wacker about 1 foot from the base. Is there anything I can do to save it? The damage wraps around tree and is about 2 inches.

Healthy mature trees likely recover from these injuries with no issue.
Young trees can be vulnerable and these type of mechanical injuries can be more serious.
If the wound completely circles the trunk of the tree, the tree can become girdled, and it can kill the tree.
If any loose bark is there, cut it carefully from the trunk.
Move any mulch away from the trunk and keep weeds down and away from touching the tree trunk.
https://www.gardeningknowhow.com/edible/fruits/plum/plum-tree-diseases.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/repairing-tree-bark-damage.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/what-is-tree-sap.htm