The year before last I cut a nice Australian Pine (Casuarina, Sheoak,this particular one was Casuarina Cunninghamia—River Sheoak) about 8", very straight and very few knots. I got five nice staves from it......
Casuarina, Sheoak, Australian Pine staves by
korey Aitkenhead, on Flickr
I roughed out the five staves in varying profiles with Axe, Hatchet, and Rasp......
Roughing out casuarina stave with shinto and rasp by
korey Aitkenhead, on Flickr
Silky Nata, perfect for profiling bow staves by
korey Aitkenhead, on Flickr
I let them season for roughly 9 months averaging 50%RH before working the first one down to roughly floor tiller dimensions without bending too much at this point. I allowed a couple weeks further drying time once brought down to rough floor tiller dimensions. The back, once the bark was removed, was seriously fissured. As Casuarina has some seriously interlocking grain, I decided to scrape the fissures down to a more-or-less flat-ish back. The first one I finished took some serious set, though it had basically a D cross section. But that wasn't the issue. See below......
Casuarina end grain by
korey Aitkenhead, on Flickr
Those radial lines you see are really brittle wood. I had to take extra care when profiling or it would tear out. But the real problem is, if your profile violates these radial "features", and it will, there is an inclination to split and splinter, so wasting all the time you put into it........ for me it was a lesson learned.
The first took bulk set, before splintering. The second and third splintered during tiller. All of them were introduced to the band saw.
I had heard tell of Australian Pine/Casuarina/Sheoak being a decent bow wood. Maybe it was the particular species I harvested, but for me, Casuarina is not a bow wood.......... There is one guy on youtube I saw with a 70"+ Casuarina bow. It had a lot of string follow, and looked a sluggish shooter. Sorry to disappoint.......