Gidday NZnuka,
Keep at it bro its differently a game where you learn by your mistakes.
Kanuka is good bow wood. But i believe its strength's lie in its ability to handle compression. It is one of our better native woods and is readily available.
Other native woods that i have tried that are good enough in tension to make a bow are generally not very good in compression.
When i lived down the coast i made a few bows out of southern rata, That stuff is tuff as but i did have a couple get compression frets around the pin knots but that was more down to my poor tillering.
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Northern rata is funny stuff, lighter and weaker than you think it should be.
Lancewood is another that seems elastic in compression but can be a bit weak under tension especially with that rope like ridges on the surface,
I have made quite a few kids bows out of that have worked quite well but not a decent adult size bow as I'm yet to find a good stave that isnt full of twist, i think it would be a good candidate for sinew backed bow.
I have made one sapling bow out of akeake, that stuff is as tuff as nails. I would love to get my hands on a decent stave of it.
Kowhai is a bit disappointing, its very good under tension but average under compression. its seems to want to soak up moister and take alot of set
you want a stave with a naturally reflex and heat treat it, may be good for sapling bows.
I have made a couple of bows using black maire as a belly wood and it is very good for that, I would like to make a self bow from it but it doesn't grow in my neck of the woods.
The one small bow i made out of Tawa seemed pretty good, i think it wants to be treated like ash or maple and made a bit wider and longer.
Tanekaha is a soft wood that is very good in tension but pretty poor under compression or though i have made a couple of bows from it that have worked one was a sapling bow the other was a sinew backed Californian type bow.
Almost all of our hard woods are diffuse porous so there is not a need to chase a ring.
We also have a lot of northern hemisphere woods here. One that is fairly abundant in my area is black locust, Its makes a nice bow and is a good teacher. You have to chase a ring but if you ever get hold of an Osage stave then you ll know what to do.
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These are just my own experiences so far others may have different ones.
Hope this helps.