This tree was on a piece of wasteland.
It had germinated on this rocky outcrop where there was water or a small stream nearby.
It has been dry this May, in fact, we have had the most unobscured sunlight on record, (Despite having one of the wettest Februarys).
I suspect the wet February washed away any ground cover soil and then the dry spell exposed the roots.
However, this resilient little tree is still thriving.