Sometimes you may need to add a bunch of forums where only the title is uniuqe, all other fields can be the same. To do this, add a forum with the name title1[,]title2[,]title3[,]title4 ... this will cause four new forums to be added named title1, title2, title3 and title4. You can add as many at once as you need, just separate each name with [,]. Note that all the new forums will become children of whichever forum you selected as the parent, and they'll share all other info as well, so if you need unique descriptions for each this may not be useful to you (though you could edit the descriptions back in later, leaving it blank initially).

For more complex bulk addition of forums and subforums, go to Admin Panel -> Forums -> Add Forums and use the bulk add options there. You can add them to a specific parent or add a set of subforums to all forums at a specified level. You can also import a CSV or other flatfile database of forums.