I've got the lyrics to 'Dying Bushman' from Phil's 'Singing Kiwi' songbook here in front of me. Slasher and Whare are the words in the chorus. Slashers are definitely pretty handy in the NZ bush - there can be lots of tough undergrowth, vines etc.
The words in the final verse are mostly native trees with Maori names:
Tawa, Matai, Pine, Hinau, Ngaio and Koromiko. So that puzzling one is 'Hinau' (Elaeocarpus dentatus).
Incidentally there's quite a few versions of this song that have been collected in NZ going right back to the 1950s. According to those singers it goes back to the 1920s.