// store root
TreeMap<Integer, String> root_path = new TreeMap<Integer, String>();
Branch root = new Branch(tree.getTreeId());
root.setDisplayName("ROOT");
root_path.put(0, "ROOT");
root.prependParentPath(root_path);
storage.addColumn(root.compileBranchId(), Tree.TREE_FAMILY(),
"branch".getBytes(MockBase.ASCII()),
(byte[])branchToStorageJson.invoke(root));
// store the first tree