Categories/Taxonomy Question - parent and child terms

Note- this was originally posted to the Drupal in Education Group. I thought it might be more relevant here:

I'm working with a few groups of instructors on sites that facilitate lesson plan creation, sharing, and discussion.

We're using taxonomy to create several vocabularies like the following:

* Syllabii
* Course Calendars
* Sequence 1 (4)
* Sequence 2
* Sequence 3 (2)
* Themes (2)
      o Art (1)
      o Identity (1)
      o Language
      o Literacy
      o ....

I've been looking for a way to make sure that any node tagged with a child term (e.g., "Art" in the example above) also gets tagged with the parent (e.g., "Themes" in the example above).

At the moment this only happens if users control-click on all of the appropriate terms.

I've seen the taxonomy force all module, but was looking for something that would tag the actual nodes with all of the appropriate terms.

If you have any hints or ideas, I'd very much appreciate the help!

Thanks!

Doug