Generally speaking, no. Each node / forum must be created at once. However in regards to permissions, child node / forums will take on the permissions of a parent node / forum. So if you have 1 parent and a bunch of children under it, you only really need to update the parent.
That's really unfortunate, It's been 8 years since i've messed with forum software, but I remember in vB this was a much easier process. If I have over 100 nodes i need to add can they be added in the db itself?