diff --git a/src/fcmp/curve_trees.cpp b/src/fcmp/curve_trees.cpp
index eaac83288..52071bd31 100644
--- a/src/fcmp/curve_trees.cpp
+++ b/src/fcmp/curve_trees.cpp
@@ -716,7 +716,7 @@ typename CurveTrees<C1, C2>::TreeExtension CurveTrees<C1, C2>::get_tree_extensio
 template<typename C1, typename C2>
 std::vector<TrimLayerInstructions> CurveTrees<C1, C2>::get_trim_instructions(
     const std::size_t old_n_leaf_tuples,
-    const std::size_t trim_n_leaf_tuples)
+    const std::size_t trim_n_leaf_tuples) const
 {
     CHECK_AND_ASSERT_THROW_MES(old_n_leaf_tuples > trim_n_leaf_tuples, "cannot trim more leaves than exist");
     CHECK_AND_ASSERT_THROW_MES(trim_n_leaf_tuples > 0, "must be trimming some leaves");
diff --git a/src/fcmp/curve_trees.h b/src/fcmp/curve_trees.h
index b4c3f10d1..77bd7bd58 100644
--- a/src/fcmp/curve_trees.h
+++ b/src/fcmp/curve_trees.h
@@ -217,7 +217,7 @@ public:
     // Get instructions useful for trimming all existing layers in the tree
     std::vector<TrimLayerInstructions> get_trim_instructions(
         const std::size_t old_n_leaf_tuples,
-        const std::size_t trim_n_leaf_tuples);
+        const std::size_t trim_n_leaf_tuples) const;
 
     // Take in the instructions useful for trimming all existing layers in the tree, all children to be trimmed from
     // each last chunk, and the existing last hashes in what will become the new last parent of each layer, and return
diff --git a/tests/unit_tests/curve_trees.cpp b/tests/unit_tests/curve_trees.cpp
index 7dbdf14b8..d552344d4 100644
--- a/tests/unit_tests/curve_trees.cpp
+++ b/tests/unit_tests/curve_trees.cpp
@@ -77,6 +77,60 @@ static bool validate_layer(const C &curve,
     return true;
 }
 //----------------------------------------------------------------------------------------------------------------------
+template<typename C_CHILD, typename C_PARENT>
+static std::vector<typename C_PARENT::Scalar> get_last_chunk_children_to_trim(const C_CHILD &c_child,
+    const fcmp::curve_trees::TrimLayerInstructions &trim_instructions,
+    const CurveTreesGlobalTree::Layer<C_CHILD> &child_layer)
+{
+    std::vector<typename C_PARENT::Scalar> children_to_trim_out;
+
+    const std::size_t new_total_children = trim_instructions.new_total_children;
+    const std::size_t old_total_children = trim_instructions.old_total_children;
+    const std::size_t new_total_parents  = trim_instructions.new_total_parents;
+    const std::size_t parent_chunk_width = trim_instructions.parent_chunk_width;
+    const std::size_t new_offset         = trim_instructions.new_offset;
+
+    CHECK_AND_ASSERT_THROW_MES(new_total_children > 0, "expected some new children");
+    CHECK_AND_ASSERT_THROW_MES(new_total_children >= new_offset, "expected more children than offset");
+    CHECK_AND_ASSERT_THROW_MES(new_total_parents > 0, "expected some new parents");
+
+    if (trim_instructions.need_last_chunk_children_to_trim)
+    {
+        std::size_t idx = ((new_total_parents - 1) * parent_chunk_width) + new_offset;
+        MDEBUG("Start trim from idx: " << idx);
+        do
+        {
+            // TODO: consolidate do while inner logic with below
+            CHECK_AND_ASSERT_THROW_MES(child_layer.size() > idx, "idx too high");
+            const auto &child_point = child_layer[idx];
+
+            auto child_scalar = c_child.point_to_cycle_scalar(child_point);
+            children_to_trim_out.push_back(std::move(child_scalar));
+
+            ++idx;
+        }
+        while ((idx < old_total_children) && (idx % parent_chunk_width != 0));
+    }
+    else if (trim_instructions.need_last_chunk_remaining_children && new_offset > 0)
+    {
+        std::size_t idx = new_total_children - new_offset;
+        MDEBUG("Start grow remaining from idx: " << idx);
+        do
+        {
+            CHECK_AND_ASSERT_THROW_MES(child_layer.size() > idx, "idx too high");
+            const auto &child_point = child_layer[idx];
+
+            auto child_scalar = c_child.point_to_cycle_scalar(child_point);
+            children_to_trim_out.push_back(std::move(child_scalar));
+
+            ++idx;
+        }
+        while ((idx < new_total_children) && (idx % parent_chunk_width != 0));
+    }
+
+    return children_to_trim_out;
+}
+//----------------------------------------------------------------------------------------------------------------------
 //----------------------------------------------------------------------------------------------------------------------
 // CurveTreesGlobalTree implementations
 //----------------------------------------------------------------------------------------------------------------------
@@ -308,60 +362,6 @@ void CurveTreesGlobalTree::reduce_tree(const CurveTreesV1::TreeReduction &tree_r
     m_tree.c2_layers.shrink_to_fit();
 }
 //----------------------------------------------------------------------------------------------------------------------
-template<typename C_CHILD, typename C_PARENT>
-static std::vector<typename C_PARENT::Scalar> get_last_chunk_children_to_trim(const C_CHILD &c_child,
-    const fcmp::curve_trees::TrimLayerInstructions &trim_instructions,
-    const CurveTreesGlobalTree::Layer<C_CHILD> &child_layer)
-{
-    std::vector<typename C_PARENT::Scalar> children_to_trim_out;
-
-    const std::size_t new_total_children = trim_instructions.new_total_children;
-    const std::size_t old_total_children = trim_instructions.old_total_children;
-    const std::size_t new_total_parents  = trim_instructions.new_total_parents;
-    const std::size_t parent_chunk_width = trim_instructions.parent_chunk_width;
-    const std::size_t new_offset         = trim_instructions.new_offset;
-
-    CHECK_AND_ASSERT_THROW_MES(new_total_children > 0, "expected some new children");
-    CHECK_AND_ASSERT_THROW_MES(new_total_children >= new_offset, "expected more children than offset");
-    CHECK_AND_ASSERT_THROW_MES(new_total_parents > 0, "expected some new parents");
-
-    if (trim_instructions.need_last_chunk_children_to_trim)
-    {
-        std::size_t idx = ((new_total_parents - 1) * parent_chunk_width) + new_offset;
-        MDEBUG("Start trim from idx: " << idx);
-        do
-        {
-            // TODO: consolidate do while inner logic with below
-            CHECK_AND_ASSERT_THROW_MES(child_layer.size() > idx, "idx too high");
-            const auto &child_point = child_layer[idx];
-
-            auto child_scalar = c_child.point_to_cycle_scalar(child_point);
-            children_to_trim_out.push_back(std::move(child_scalar));
-
-            ++idx;
-        }
-        while ((idx < old_total_children) && (idx % parent_chunk_width != 0));
-    }
-    else if (trim_instructions.need_last_chunk_remaining_children && new_offset > 0)
-    {
-        std::size_t idx = new_total_children - new_offset;
-        MDEBUG("Start grow remaining from idx: " << idx);
-        do
-        {
-            CHECK_AND_ASSERT_THROW_MES(child_layer.size() > idx, "idx too high");
-            const auto &child_point = child_layer[idx];
-
-            auto child_scalar = c_child.point_to_cycle_scalar(child_point);
-            children_to_trim_out.push_back(std::move(child_scalar));
-
-            ++idx;
-        }
-        while ((idx < new_total_children) && (idx % parent_chunk_width != 0));
-    }
-
-    return children_to_trim_out;
-}
-//----------------------------------------------------------------------------------------------------------------------
 // TODO: template
 CurveTreesV1::LastChunkChildrenToTrim CurveTreesGlobalTree::get_all_last_chunk_children_to_trim(
     const std::vector<fcmp::curve_trees::TrimLayerInstructions> &trim_instructions)