Unable to seperate normal and hidden folder such as “Forms” [SPFolder Object Model ]

Question

While performing certain task in a console application, i am unable to separate normal folder and hidden ones such as "Forms","FormServerTemplates" etc. I am using SPFolder in the obejct model. I have tried both FolderObject.property.count=21 and FolderObject.item==null, but none of these seems to filter the hidden folders.

Scenario : To copy all folders and files inside root folder of document library. Excluding hidden folders such as "Forms", "FormServerTemplates" etc.

static void traverseFolder(SPFolder fold, string path)
        {

            try
            {

                if (!(fold.Item==null))
                {

                    var Listdir = path + @"\" + fold.Name.ToString();
                    string listpath = Listdir.ToString();
                    if (!Directory.Exists(Listdir))
                        Directory.CreateDirectory(Listdir);


                    foreach (SPFolder subFold in fold.SubFolders)
                    {
                        if (!(subFold.Item==null))
                            traverseFolder(subFold, listpath);
                    }

                    foreach (SPFile file in fold.Files)
                    {
                        byte[] binFile = file.OpenBinary();

                        System.IO.FileStream fstream =

                        System.IO.File.Create(listpath + "\\" + file.Name);

                        fstream.Write(binFile, 0, binFile.Length);

                        //Console.WriteLine(file.Name);
                    }

                }      //Console.WriteLine(item.File.Name);
            }

            catch (Exception ex)
            {
                EventLog myException = new EventLog("");
                myException.Source = "SiteCol File Copy Exception";
                myException.WriteEntry("Error in copying " + ex.Message,EventLogEntryType.Error);
            }


        }

Is there any other way to separate?

Thanks