diff --git a/lib/cretonne/src/bforest/map.rs b/lib/cretonne/src/bforest/map.rs
index 23cac5600d..601e9febe6 100644
--- a/lib/cretonne/src/bforest/map.rs
+++ b/lib/cretonne/src/bforest/map.rs
@@ -61,6 +61,11 @@ where
 ///
 /// This is not a general-purpose replacement for `BTreeMap`. See the [module
 /// documentation](index.html) for more information about design tradeoffs.
+///
+/// Maps can be cloned, but that operation should only be used as part of cloning the whole forest
+/// they belong to. *Cloning a map does not allocate new memory for the clone*. It creates an alias
+/// of the same memory.
+#[derive(Clone)]
 pub struct Map<K, V, C>
 where
     K: Copy,
@@ -145,6 +150,17 @@ where
     }
 }
 
+impl<K, V, C> Default for Map<K, V, C>
+where
+    K: Copy,
+    V: Copy,
+    C: Comparator<K>,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 #[cfg(test)]
 impl<K, V, C> Map<K, V, C>
 where
diff --git a/lib/cretonne/src/bforest/set.rs b/lib/cretonne/src/bforest/set.rs
index 4956a26147..025efc0225 100644
--- a/lib/cretonne/src/bforest/set.rs
+++ b/lib/cretonne/src/bforest/set.rs
@@ -58,6 +58,11 @@ where
 ///
 /// This is not a general-purpose replacement for `BTreeSet`. See the [module
 /// documentation](index.html) for more information about design tradeoffs.
+///
+/// Sets can be cloned, but that operation should only be used as part of cloning the whole forest
+/// they belong to. *Cloning a set does not allocate new memory for the clone*. It creates an alias
+/// of the same memory.
+#[derive(Clone)]
 pub struct Set<K, C>
 where
     K: Copy,
@@ -142,6 +147,16 @@ where
     }
 }
 
+impl<K, C> Default for Set<K, C>
+where
+    K: Copy,
+    C: Comparator<K>,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 /// A position in a `Set` used to navigate and modify the ordered set.
 ///
 /// A cursor always points at an element in the set, or "off the end" which is a position after the