Removing the root zone means that your server will not be able to resolve requests on the internet and that it will indeed have to forward requests to another server. This is a great thing to do when you don't want any of your internal DNS data getting out on the internet where hackers can see, so you would combine it with a caching DNS server outside your firewall.
However, if you can't change the "Forwarders Disabled" property of the server, I would suggest checking with other IT people at your company before doing anything like deleting the root zone. Especially if this DNS server is your initial domain controller connected with Active Directory. If DC / AD is the case, DO NOT USE THIS SERVER TO FORWARD. Lots of external people could get access to information you don't want them to have. A member server or, as above, a caching only server is the best way to go for a forwarder.
Catadmin - MCSA