It is possible that your cherry tree will continue to live for several years without any intervention on your part.  In fact, an otherwise healthy tree will isolate such a wound, surround it with a corky material from the inside out, and go on living in spite of the wound.  However, there are a couple of issues that you need to be aware of.  The wound will allow boring insects entry into the tree's vascular system (located just under the bark) and they will kill the tree within a year of two.  Also, the wound is allowing water to infiltrate the heartwood.  The heartwood of every tree is simply dead wood whose purpose is to hold the tree upright.  As long as the bark protects the heartwood from getting wet, the heartwood will not rot, but when the bark is compromised, and rot sets in, the tree is doomed to fall in a wind storm.  Unfortunately, the tree needs oxygen in order to 'heal' itself, so sealants are no longer recommended.  It may be possible for you to devise a skirting device to divert water away from the wound, but it may be too late.  Your only recourse is to monitor the tree carefully for any signs of further deterioration and be prepared to remove it before it becomes a threat to property or safety.
LS