If you use a branch , conifers in compression ,get stronger on the lower side (compression side) and weaker on the upper side (tension side) .So you might be successful making a nice bow from the bottom side of one of the branches. It would be a backwards bow ,with the the middle of the branch being the back of the bow .And the sapwood or outside of the branch being the belly of the bow.The bow should gain quite a bit of reflex. I would probably back it with sinew.
I've been wanting to try a bow like this for awhile now.
Ralph