diff --git a/zebra-chain/src/orchard/tree.rs b/zebra-chain/src/orchard/tree.rs
index c8cab34b..a2c86a3e 100644
--- a/zebra-chain/src/orchard/tree.rs
+++ b/zebra-chain/src/orchard/tree.rs
@@ -221,7 +221,17 @@ pub struct NoteCommitmentTree {
     /// It consists of nodes along the rightmost (newer) branch of the tree that
     /// has non-empty nodes. Upper (near root) empty nodes of the branch are not
     /// stored.
+    ///
+    /// # Consensus
+    ///
+    /// > [NU5 onward] A block MUST NOT add Orchard note commitments that would result in the Orchard note
+    /// > commitment tree exceeding its capacity of 2^(MerkleDepth^Orchard) leaf nodes.
+    ///
+    /// <https://zips.z.cash/protocol/protocol.pdf#merkletree>
+    ///
+    /// Note: MerkleDepth^Orchard = MERKLE_DEPTH = 32.
     inner: bridgetree::Frontier<Node, { MERKLE_DEPTH as u8 }>,
+
     /// A cached root of the tree.
     ///
     /// Every time the root is computed by [`Self::root`] it is cached here,
diff --git a/zebra-chain/src/sapling/tree.rs b/zebra-chain/src/sapling/tree.rs
index 1f02d6f4..15af1ba7 100644
--- a/zebra-chain/src/sapling/tree.rs
+++ b/zebra-chain/src/sapling/tree.rs
@@ -184,7 +184,17 @@ pub struct NoteCommitmentTree {
     /// It consists of nodes along the rightmost (newer) branch of the tree that
     /// has non-empty nodes. Upper (near root) empty nodes of the branch are not
     /// stored.
+    ///
+    /// # Consensus
+    ///
+    /// > [Sapling onward] A block MUST NOT add Sapling note commitments that would result in the Sapling note
+    /// > commitment tree exceeding its capacity of 2^(MerkleDepth^Sapling) leaf nodes.
+    ///
+    /// <https://zips.z.cash/protocol/protocol.pdf#merkletree>
+    ///
+    /// Note: MerkleDepth^Sapling = MERKLE_DEPTH = 32.
     inner: bridgetree::Frontier<Node, { MERKLE_DEPTH as u8 }>,
+
     /// A cached root of the tree.
     ///
     /// Every time the root is computed by [`Self::root`] it is cached here,
diff --git a/zebra-chain/src/sprout/tree.rs b/zebra-chain/src/sprout/tree.rs
index 06fd59de..ffc2a0c2 100644
--- a/zebra-chain/src/sprout/tree.rs
+++ b/zebra-chain/src/sprout/tree.rs
@@ -209,6 +209,15 @@ pub struct NoteCommitmentTree {
     /// consists of nodes along the rightmost (newer) branch of the tree that
     /// has non-empty nodes. Upper (near root) empty nodes of the branch are not
     /// stored.
+    ///
+    /// # Consensus
+    ///
+    /// > A block MUST NOT add Sprout note commitments that would result in the Sprout note commitment tree
+    /// > exceeding its capacity of 2^(MerkleDepth^Sprout) leaf nodes.
+    ///
+    /// <https://zips.z.cash/protocol/protocol.pdf#merkletree>
+    ///
+    /// Note: MerkleDepth^Sprout = MERKLE_DEPTH = 29.
     inner: bridgetree::Frontier<Node, { MERKLE_DEPTH as u8 }>,
 
     /// A cached root of the tree.