Well, you can create usergroups, permissions and forums. Technically speaking yes, you could create a usergroup for each user. Start by making a usergroup called say 'user 1', a forum called 'forum 1' and as long as you have at least a permission set to allow or deny access, you could set 'user 1's' permissions to allow access on 'forum 1', and deny access to all other groups on 'forum 1'.. and so on with 'user 2', 'forum 2' etc..

So it would work, albeit a long winded process.. Might be fine for 10 or 15 members, unfortunately I don't believe there is a way to automate this upon user registration.