Both the zones are used for name resolution but when we are used stub and when we are used forwarder. I am trying to say as small as possible.
Ex: We need a trust between domain A and domain B and am a system admin of domain A and in future any changes happen in domain B, we may not get those update , here best is stub, why? Because stub is automated process and the changes will update automatically.
Forwarder is a manual process. Assume admin of domain B has changed the DNS server but I don’t have the update, here problem comes-up.
If you are aware of the activity of domain B then you can use the forwarder.
N.B: You can not create stub zone and forwarder together with the same zone name.