[@mercime]

Yes you can. However, installing BuddyPress only for the forum feature alone is overkill if you’re not going use the social networking components of the plugin. The BuddyPress internal bbPress forums are associated to groups by default. I would suggest that you install a WP or WP-compatible forum plugin or software like:
https://wordpress.org/extend/plugins/forum-server/
https://wordpress.org/extend/plugins/mingle-forum/
http://simple-press.com/
or integrate external bbPress plugin with your WordPress site.

If you do intend to use BuddyPress components plus the forums, before you install and activate BuddyPress, you would need to make your WordPress theme compatible with BuddyPress via BP Template Pack plugin or by building a child theme of bp-default theme that comes with BuddyPress plugin first. If you are going the first theme route – BP template pack – then you could add the necessary link to your BP components including forums by adding the links listed in ul#nav seen here
https://trac.buddypress.org/browser/tags/1.2.8/bp-themes/bp-default/header.php#L46