Dana, thats great!!
I went for a boat / hike trip up the columbia river yesterday - had my hand saw in my backpack (of course). There's groves of sumac up in those desert canyons - but for the life of me, I couldn't find a single one that was remotely straight enough to even consider for a bow. Not even for a snakey bow. They grow like vines.
You wouldn't happen to have a before picture of your stave, just after it was cut, would you?
Anyone ever try Elderberry? There are some very big "trees" of this stuff up in there too. I'm going to go find one and give them a try too - I know they're pithy inside, but some of these were 6 or so inches in diam. There must be some good wood around the pith on those.
Anyway, Dana, I love that bow - and your drive to try the new wood.
Mike