diff --git a/src/Newickform.c b/src/Newickform.c
index abd18e5e..0214f788 100644
--- a/src/Newickform.c
+++ b/src/Newickform.c
@@ -245,8 +245,9 @@ newick_node* build_newick_tree(char * filename, FILE *vcf_file_pointer,int * snp
   // Allocate memory to store all sequences
   // N.B. this can be reduced once memory management improves
   int num_stored_nodes = num_nodes;
-  char ** node_sequences = (char **) calloc((number_of_snps + 1)*num_stored_nodes,sizeof(char));
-  char ** node_names = (char **) calloc(MAX_SAMPLE_NAME_SIZE*num_stored_nodes,sizeof(char));
+  char ** node_sequences = calloc((number_of_snps + 1) * num_stored_nodes, sizeof(char*));
+  char ** node_names = calloc(MAX_SAMPLE_NAME_SIZE*num_stored_nodes,sizeof(char));
+
   for (int seq_store_index = 0; seq_store_index  < num_stored_nodes; ++seq_store_index)
   {
     node_names[seq_store_index] = " ";