diff --git a/src/gtree.rs b/src/gtree.rs
index ba69ecd..401767c 100644
--- a/src/gtree.rs
+++ b/src/gtree.rs
@@ -142,7 +142,7 @@ impl InodeIdx {
     ///
     /// 2. For the root node, to indicate that it has no parent.
     #[inline]
-    const fn dangling() -> Self {
+    pub(crate) const fn dangling() -> Self {
         Self(usize::MAX)
     }
 
@@ -182,10 +182,15 @@ impl<L> LeafIdx<L> {
     /// Returns a "dangling" index which doesn't point to any leaf of the
     /// Gtree.
     #[inline]
-    pub const fn dangling() -> Self {
+    pub(crate) const fn dangling() -> Self {
         Self::new(usize::MAX)
     }
 
+    #[inline]
+    pub(crate) fn into_usize(self) -> usize {
+        self.idx
+    }
+
     #[inline]
     const fn new(idx: usize) -> Self {
         Self { idx, _pd: PhantomData }
diff --git a/src/run_tree.rs b/src/run_tree.rs
index d19d4f7..be23e7d 100644
--- a/src/run_tree.rs
+++ b/src/run_tree.rs
@@ -1129,6 +1129,18 @@ mod encode {
     use crate::gtree::{encode::InodeDecodeError, Inode, InodeIdx, Lnode};
     use crate::run_indices::{Fragment, Fragments, ReplicaIndices};
 
+    impl EditRun {
+        #[inline(always)]
+        fn dummy() -> Self {
+            Self {
+                text: Text::new(0, 0..0),
+                run_ts: 0,
+                lamport_ts: 0,
+                is_deleted: false,
+            }
+        }
+    }
+
     impl Encode for RunTree {
         #[inline]
         fn encode(&self, buf: &mut Vec<u8>) {
@@ -1136,6 +1148,8 @@ mod encode {
 
             (indices.len() as u64).encode(buf);
 
+            (self.gtree.num_leaves() as u64).encode(buf);
+
             for (&replica_id, indices) in indices {
                 ReplicaRuns::new(replica_id, indices, &self.gtree).encode(buf);
             }
@@ -1210,10 +1224,17 @@ mod encode {
 
         #[inline]
         fn decode(buf: &[u8]) -> Result<(Self, &[u8]), Self::Error> {
-            let (num_replicas, mut buf) = u64::decode(buf)?;
+            let (num_replicas, buf) = u64::decode(buf)?;
+
+            let (num_leaves, mut buf) = u64::decode(buf)?;
 
             let mut ctx = RunTreeDecodeCtx::default();
 
+            let dummy_lnode =
+                Lnode::new(EditRun::dummy(), InodeIdx::dangling());
+
+            ctx.lnodes.resize(num_leaves as usize, dummy_lnode);
+
             for _ in 0..num_replicas {
                 ((), buf) = ReplicaRuns::decode(buf, &mut ctx)?;
                 ctx.replica_indices.clear();
@@ -1411,7 +1432,8 @@ mod encode {
             let edit_run =
                 EditRun::new(text, ctx.run_ts, lamport_ts, is_deleted);
 
-            ctx.lnodes.push(Lnode::new(edit_run, parent_idx));
+            ctx.lnodes[leaf_idx.into_usize()] =
+                Lnode::new(edit_run, parent_idx);
 
             Ok(((), buf))
         }