To archive the Discussion Board, go to the Discussion Board and click Search. See screenshot below.

In the search field, enter the after date (i.e. the start of term) and enter the before date (i.e. the end of term). Click the Go button. See screenshot below.

In the search results page, click the All link and when all the check boxes are selected, click the Print Preview button. See screenshot below.

A pop-up window appears, you may print all the threads or copy and paste the threads into a text editor or a Word document. See screenshot below.