diff --git a/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol b/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
index ce61113..ad17456 100644
--- a/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
+++ b/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
@@ -31,6 +31,7 @@ library IncrementalBinaryTree {
     uint8 depth,
     uint256 zero
   ) public {
+    require(zero < SNARK_SCALAR_FIELD, "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD");
     require(depth > 0 && depth <= MAX_DEPTH, "IncrementalBinaryTree: tree depth must be between 1 and 32");
 
     self.depth = depth;
diff --git a/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol b/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol
index a49157c..c0d22c8 100644
--- a/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol
+++ b/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol
@@ -31,6 +31,7 @@ library IncrementalQuinTree {
     uint8 depth,
     uint256 zero
   ) public {
+    require(zero < SNARK_SCALAR_FIELD, "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD");
     require(depth > 0 && depth <= MAX_DEPTH, "IncrementalQuinTree: tree depth must be between 1 and 32");
 
     self.depth = depth;