diff --git a/poincare/include/poincare/tree_pool.h b/poincare/include/poincare/tree_pool.h
index 83d4cd987..e88ed52a4 100644
--- a/poincare/include/poincare/tree_pool.h
+++ b/poincare/include/poincare/tree_pool.h
@@ -65,9 +65,11 @@ public:
 
   int numberOfNodes() const {
     int count = 0;
-    AllPool nodes = const_cast<TreePool *>(this)->allNodes();
-    for (TreeNode * t : nodes) {
+    TreeNode * firstNode = first();
+    TreeNode * lastNode = last();
+    while (firstNode != lastNode) {
       count++;
+      firstNode = firstNode->next();
     }
     return count;
   }
diff --git a/poincare/src/tree_node.cpp b/poincare/src/tree_node.cpp
index 7e59cdbad..56c863bb3 100644
--- a/poincare/src/tree_node.cpp
+++ b/poincare/src/tree_node.cpp
@@ -93,8 +93,11 @@ TreeNode * TreeNode::editableRootTree() {
 
 int TreeNode::numberOfDescendants(bool includeSelf) const {
   int result = includeSelf ? 1 : 0;
-  for (TreeNode * child : depthFirstChildren()) {
+  TreeNode * nextSiblingNode = nextSibling();
+  TreeNode * currentNode = next();
+  while (currentNode != nextSiblingNode) {
     result++;
+    currentNode = currentNode->next();
   }
   return result;
 }