the thought of non American wood bows popped into my head. Why do we never see them?
We see bows from non-American woods all the time! Plenty of English yew (not the same as your Pacific yew), ipé (from South America), bamboo (from Asia), elms (from Europe) and so on. This forum just happens to have an American origin, since it is based on the Primitive Archer magazine. The messageboard Trad Gang is even more American based, while Paleo Planet seems to be a bit more international. But also Primitive Archery has many 'foreign' people (if you consider Americans the native ones), but you just have to know where to look. Not everyone fills in the 'location' in their profile. Still, when I am using Black Locust, I am using a stinking exotic wood! I live in Europe and Black Locust is not native here. So to me, Black Locust is an exotic wood from America so I am still using a foreign wood.
I am not completely sure if your question is specifically to New Zealand woods/bowyers, or to all non-American woods/bowyers in general. But many regions also have their own local archery forums. The fact that this forum is (of course) in English, may deter many foreign people that don't speak English. And Australian and/or New Zealand people may rather post at their local message board
OZ Bow. If you were to speak German, the message board
Flethers Corner will be really interesting to you. Over on Paleo Planet, a very interesting topic was started about
less familiar bow woods. You'll find some very unique woods being used their, mainly European woods.
By the way, the New Zealand wood 'puriri' might have a high specific gravity (SG), but that does not automatically make it a good bow wood. Many true bow woods have an SG of around 0.6 to 0.7. The woods also needs to be elastic, not just have a high SG. Over the years, I've seen a few Australian people appear on Paleo Planet and have gained some knowledge from their posts. Okay, New Zealand is still a long way from Australia, but due to the reasons Crogacht mentions, I've not seen New Zealanders I think. Many Australian woods appear to have a high density but lack some elasticity. There's an abundance of eucalyptus over there, and some of them do actually work for bows. Also mangrove species can be really good. There's just not many Australian/New Zealand bowyers around, so it's easy to overlook what little they do post about their local bow woods.