diff --git a/src/flow/binary/balancing.rs b/src/flow/binary/balancing.rs
index 9acff06..ba49efb 100644
--- a/src/flow/binary/balancing.rs
+++ b/src/flow/binary/balancing.rs
@@ -110,3 +110,19 @@ impl<'a, BT: BinaryTreesUnbalanced<'a>> BinaryTreesTreeOf<'a> for BalancedTrees<
         })
     }
 }
+
+impl<'a, BT: BinaryTreesUnbalanced<'a> + BinaryTreesEmpty<'a>> BinaryTreesEmpty<'a>
+    for BalancedTrees<BT>
+{
+    fn empty(&self) -> Self::Tree {
+        self.0.empty()
+    }
+
+    fn split_key_empty(
+        &self,
+        tree: Self::Tree,
+        key: Self::Key,
+    ) -> BTWrap<'a, Self, KeySplit<'a, Self>> {
+        self.0.split_key_empty(tree, key)
+    }
+}