@Override
    protected void setParent(Node parent) {
        super.setParent(parent);
        if (parent == null) {
            // if the terrain is being detached
            clearCaches();
        }
    }
Called internally by com.jme3.util.clone.Cloner.  Do not call directly.
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainQuad.java