Yes, if you use your WordPress site as the SSO provider for your forum, there is an action hook that you can use to limit which users are able to login to the forum. The hook is called wpdc_sso_provider_before_sso_redirect. Some code like this, added to a plugin or your theme’s functions.php file will work. You will need to figure out how to check the user’s WooMembership level.
add_action( 'wpdc_sso_provider_before_sso_redirect', 'wpdc_custom_check_user_membership', 10, 2 );
function wpdc_custom_check_user_membership( $user_id, $user ) {
if ( /* Some condition that returns true if the user doesn't meet the membership requirement */ ) {
wp_safe_redirect( home_url() );
exit;
}
}