These openings in the bark are where the tissue under the bark died.  I can't say why this occurred.  Kentucky coffee tree is not prone to fungal disease that cause dead areas such as these.  Borers (insects that feed under bark) can cause similar damage but I do not see the trails the larvae leave on the bare wood in these areas.  Borers can feed on any tree but their damage is usually limited and not on-going.  Environmental factors such as low temperature injury can damage tissue also.  At this point look at the overall health of the tree to see what real effect to the plant.  Are leaves looking good throughout the plant?  If so, focus on the cultural care: watering during periods of drought, this tree handles dry conditions fairly well.  If tree is growing quickly as many Kentucky coffee trees do, than you may not need to fertilize.  Good care of the tree such as mulching around the base to protect from mower and weed whip injury and water when needed can help to maintain plant vigor. The University of Illinois and North Carolina State University both list this tree doing best in moist soils, though they can handle some drought.