diff --git a/src/flow/binary.rs b/src/flow/binary.rs
index b6d722d..31a15fb 100644
--- a/src/flow/binary.rs
+++ b/src/flow/binary.rs
@@ -1,4 +1,5 @@
 pub mod avl;
+pub mod balancing;
 pub mod bounds;
 
 use crate::flow::comparator::*;
@@ -24,10 +25,13 @@ pub trait BinaryTrees<'a>: FunctorContext<'a, T = Self::_Tm> + Clone {
 
     fn comparator(&self) -> &Self::Comparator;
     fn split(&self, node: &Self::Node) -> Split<'a, Self>;
-    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree>;
     fn resolve(&self, reference: &Self::Reference) -> BTWrap<'a, Self, Self::Node>;
     fn equal(&self, rl: &Self::Reference, rr: &Self::Reference) -> bool;
     fn refer(&self, tree: &Self::Tree) -> Option<Self::Reference>;
+}
+
+pub trait BinaryTreesTreeOf<'a>: BinaryTrees<'a> {
+    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree>;
 
     fn tree_bind(self, fnode: BTWrap<'a, Self, Self::Node>) -> BTWrap<'a, Self, Self::Tree> {
         Self::bind(fnode, move |node| self.tree_of(node))
@@ -44,7 +48,7 @@ pub trait BinaryTreesEmpty<'a>: BinaryTrees<'a> {
     ) -> BTWrap<'a, Self, KeySplit<'a, Self>>;
 }
 
-pub trait BinaryTreesMutable<'a>: BinaryTreesEmpty<'a> {
+pub trait BinaryTreesMutable<'a>: BinaryTreesEmpty<'a> + BinaryTreesTreeOf<'a> {
     fn join_key(
         self,
         tl: Self::Tree,
diff --git a/src/flow/binary/avl.rs b/src/flow/binary/avl.rs
index cf57568..ede31bf 100644
--- a/src/flow/binary/avl.rs
+++ b/src/flow/binary/avl.rs
@@ -1,6 +1,8 @@
 use super::*;
 
-pub trait BinaryTreesAvl<'a>: BinaryTreesHeight<'a> + BinaryTreesTryJoin<'a> {
+pub trait BinaryTreesAvl<'a>:
+    BinaryTreesHeight<'a> + BinaryTreesTreeOf<'a> + BinaryTreesTryJoin<'a>
+{
     fn assume_node(&self, tree: &Self::Tree) -> BTWrap<'a, Self, Self::Node> {
         match self.refer(tree) {
             Some(reference) => self.resolve(&reference),
@@ -68,4 +70,7 @@ pub trait BinaryTreesAvl<'a>: BinaryTreesHeight<'a> + BinaryTreesTryJoin<'a> {
     }
 }
 
-impl<'a, BT: BinaryTreesHeight<'a> + BinaryTreesTryJoin<'a>> BinaryTreesAvl<'a> for BT {}
+impl<'a, BT: BinaryTreesHeight<'a> + BinaryTreesTreeOf<'a> + BinaryTreesTryJoin<'a>>
+    BinaryTreesAvl<'a> for BT
+{
+}
diff --git a/src/flow/binary/balancing.rs b/src/flow/binary/balancing.rs
new file mode 100644
index 0000000..e69de29
diff --git a/src/flow/binary/bounds/bound.rs b/src/flow/binary/bounds/bound.rs
index 8827ad2..8848fe2 100644
--- a/src/flow/binary/bounds/bound.rs
+++ b/src/flow/binary/bounds/bound.rs
@@ -70,13 +70,6 @@ impl<'a, BT: BinaryTreesBindable<'a>> BinaryTrees<'a> for BoundTrees<BT> {
         )
     }
 
-    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree> {
-        Self::fmap(self.0.tree_of(node.node), move |tree| Bound {
-            bound: tree,
-            bounds: node.bounds,
-        })
-    }
-
     fn resolve(&self, reference: &Self::Reference) -> BTWrap<'a, Self, Self::Node> {
         let ctx = self.clone();
         let bounds = reference.bounds.clone();
@@ -109,6 +102,17 @@ impl<'a, BT: BinaryTreesBindable<'a>> BinaryTrees<'a> for BoundTrees<BT> {
     }
 }
 
+impl<'a, BT: BinaryTreesBindable<'a> + BinaryTreesTreeOf<'a>> BinaryTreesTreeOf<'a>
+    for BoundTrees<BT>
+{
+    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree> {
+        Self::fmap(self.0.tree_of(node.node), move |tree| Bound {
+            bound: tree,
+            bounds: node.bounds,
+        })
+    }
+}
+
 impl<'a, BT: BinaryTreesBindable<'a> + BinaryTreesEmpty<'a>> BinaryTreesEmpty<'a>
     for BoundTrees<BT>
 {
diff --git a/src/mrds/trees/avl.rs b/src/mrds/trees/avl.rs
index 2ab4112..ed17069 100644
--- a/src/mrds/trees/avl.rs
+++ b/src/mrds/trees/avl.rs
@@ -126,15 +126,6 @@ impl<'a, A: 'a + PartialOrd + Clone> BinaryTrees<'a> for AvlTs<A> {
         (node.l.clone(), node.r.clone(), node.key.clone())
     }
 
-    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree> {
-        AvlT {
-            height: std::cmp::max(node.l.height, node.r.height)
-                .checked_add(1)
-                .unwrap(),
-            reference: Some(AvlR { node: node.into() }),
-        }
-    }
-
     fn resolve(&self, reference: &Self::Reference) -> BTWrap<'a, Self, Self::Node> {
         reference.node.as_ref().clone()
     }
@@ -148,6 +139,17 @@ impl<'a, A: 'a + PartialOrd + Clone> BinaryTrees<'a> for AvlTs<A> {
     }
 }
 
+impl<'a, A: 'a + PartialOrd + Clone> BinaryTreesTreeOf<'a> for AvlTs<A> {
+    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree> {
+        AvlT {
+            height: std::cmp::max(node.l.height, node.r.height)
+                .checked_add(1)
+                .unwrap(),
+            reference: Some(AvlR { node: node.into() }),
+        }
+    }
+}
+
 impl<'a, A: 'a + PartialOrd + Clone> BinaryTreesEmpty<'a> for AvlTs<A> {
     fn empty(&self) -> Self::Tree {
         AvlT {
diff --git a/src/rstd/collections/avl/context.rs b/src/rstd/collections/avl/context.rs
index c046b78..eb2afb9 100644
--- a/src/rstd/collections/avl/context.rs
+++ b/src/rstd/collections/avl/context.rs
@@ -48,13 +48,6 @@ impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A
         node.split()
     }
 
-    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree> {
-        match node.into_tree() {
-            Ok(tree) => Self::pure(tree),
-            Err(e) => Self::fail(ResolutionError::Parse(e)),
-        }
-    }
-
     fn resolve(&self, reference: &Self::Reference) -> BTWrap<'a, Self, Self::Node> {
         Ctx::stuff(reference.resolve(self.comparator.clone()))
     }
@@ -68,6 +61,17 @@ impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A
     }
 }
 
+impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A>>
+    BinaryTreesTreeOf<'a> for BoundContext<'a, Ctx, A, C>
+{
+    fn tree_of(&self, node: Self::Node) -> BTWrap<'a, Self, Self::Tree> {
+        match node.into_tree() {
+            Ok(tree) => Self::pure(tree),
+            Err(e) => Self::fail(ResolutionError::Parse(e)),
+        }
+    }
+}
+
 impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A>>
     BinaryTreesEmpty<'a> for BoundContext<'a, Ctx, A, C>
 {