diff --git a/core/CCKTree.ml b/core/CCKTree.ml
index f19fd14d..3813e5b7 100644
--- a/core/CCKTree.ml
+++ b/core/CCKTree.ml
@@ -294,5 +294,20 @@ module Dot = struct
     Format.pp_print_flush fmt ()
 
   let pp_single name buf t = pp buf (singleton ~name t)
+
+  let print_to_file filename g =
+    let oc = open_out filename in
+    let fmt = Format.formatter_of_out_channel oc in
+    try
+      print fmt g;
+      Format.pp_print_flush fmt ();
+      close_out oc
+    with e ->
+      close_out oc;
+      raise e
+
+  let to_file ?(name="graph") filename trees =
+    let g = make ~name trees in
+    print_to_file filename g
 end
 
diff --git a/core/CCKTree.mli b/core/CCKTree.mli
index 1235ebc0..8137fe19 100644
--- a/core/CCKTree.mli
+++ b/core/CCKTree.mli
@@ -126,5 +126,18 @@ module Dot : sig
   val pp_single : string -> attribute list t printer
 
   val print : graph formatter
+  (** Printer with indentation, etc.
+      @since NEXT_RELEASE *)
+
+  val print_to_file : string -> graph -> unit
+  (** [print_to_file filename g] prints [g] into a file whose name
+      is [filename].
+      @since NEXT_RELEASE *)
+
+  val to_file : ?name:string -> string -> attribute list t list -> unit
+  (** [to_file filename trees] makes a graph out of the trees, opens the
+      file [filename] and prints the graph into the file.
+      @param name name of the graph
+      @since NEXT_RELEASE *)
 end