Hey Rick.
Its been a loong time since Ive been on the forum, too much work not enuff play. Its good to see a fellow Alaskan on here. I live on the Kenai, and my brother in law(AK Bowman) lives down here too. We have been playing arround with the birch for a while and have had mixed success. He made a cool bow from Kenai Birch that he left the bark on. It shoots good but took a bit of set, I think he posted it here someplace. Ive had the most luck with cutting birch up by Fairbanks or further north even. Seems like alot of the birch that grows on the peninsula twists as it grows. I think that it is because of the super dense spruce thickets and they have to fight for the sunlight, but a friend of mine thinks its because the area I get mine from the wind is always blowing off a glacier and forces the trees to twist. Like evryone has said wide flat limbs seem to be the trick, birch does make a good bow wood and heat treating the belly seems to help with belly compression problems too.
There is a guy I met on Paleo Planet named Fiddler49 thats lives in Spenard I think. He is a good dude and uses birch as well. If your ever down on the Kenai look me up. Good luck.
Moose
