I planted a Weeping Cherry in my front yard approximately 1.5 years ago. It bloomed brilliantly this year and seemed to thrive. I noticed recently that at the base of the tree, a 6" vertical and 2" wide section of bark is missing at the base of the tree, exposing what appears to be two separate smaller trunks. The tree is 6.5' tall and 3" diameter trunk. Can anyone tell me why this has happened and if there is anything that should be done. I live in Tennessee.