there is a forum duplicator from an old guy here, i just don't remember if it works with 3.6.x
check and ask:
https://vborg.vbsupport.ru/showthread.php?t=83213
with Chris technique, you will have to Rebuild Counters, or your forums will not appear.
EDIT: changed the url to the 3.5 version of the hack... works on 3.6 !!!
(thanks to remember me the version Chris !!)