Well, I suppose 'hollow like an old tree trunk' is a pretty accurate description of BUFORA these days, but I couldn't make out why a Norwegian composer would be celebrating a British UFO group. The catalogue helpfully gave an English translation of the title as 'Huldre - transhumans'. This was even more puzzling. I found that American ufologist Mac Tonnies was claiming to be a practitioner of 'transhuman ufology' HERE, but its relationship to Norwegian piano music seemed marginal. Then I noticed that the word was actually transhumance and all became clear(ish).
Another source told me that transhumance is the "transfer of livestock from one grazing ground to another, as from lowlands to highlands, with the changing of seasons".
So in Norwegian, bufora is the practice of moving cattle around in large numbers. Having learned this, I wish I could make some smart, satirical comment, but I just don't seem to be able to.
By the way, if you'd like to hear some of Tveitt's music, and it's really rather lovely, here's a link to buy the CD with the bufora piece on it in an orchestral arrangement.: