You should put a trunk guard on your tree. They're usually plastic mesh or solid, simply fit it around the bottom of the trunk and snap it into place, and it'll help protect it from the elements. Check your local garden center or hardware store. I would find one that's lighter in color, and allows air flow (so it doesn't build up excessive heat or trap moisture).

The damage looks like it was originally from frost, sun scald, or even physical bumps when dug up and transported. An animal such as a rabbit could contribute, or make the damage much worse. It's a healthy tree, and it will continue to grow and thrive, but best to do diligence and protect the trunk from further damage. 

Some reading: https://bygl.osu.edu/node/1246

Best of luck!

You're very welcome.