How to back up and restore firefox tree style tabs?

I use the popular Tree Style Tab firefox extension. How can I back up all open tabs and later restore them, yielding the same tab tree? The backup could be saved to the bookmarks database, or to a separate file. New backups should not overwrite old backups.

I don't really want to back up the whole session, just the tabs. Ideally I'd like to schedule a task within firefox to create a new backup daily or at browser close time.

Note that right click and "Bookmark this Tree..." works for sub-trees, but so far as I can see, not for the entire tree (you can't bookmark all open tabs this way). Meanwhile, right click and "Bookmark All Tabs..." does save all of the tabs, but loses the tree structure.

I also use that plugin and I use the Session Manager plugin for this exact purpose. When I'm developing I often end up with a load of tabs about a particular thing and want to store them in the same tab tree order, but wouldn't want to bookmark them. I'd have tons of unwanted bookmarks.

I just save the window as a backup session and give it a relevant name, and category if required, and then when I want to retrieve them just load the session. It closes all the other tabs and opens the backup session.

I know you say you don't want to store the session, but from your description its ability to store the tab tree is just what you're looking for?

It turns out that my question was incorrect: "Bookmark All Tabs..." works fine for this purpose. Though the list of bookmarks under the Bookmarks menu is displayed without the tree structure, that structure is present, and the "Open All in Tabs" menu item in the Bookmarks submenu restores that tree structure.