I would still go for hazel:
1) it grows everywhere in N-France, Luxemburg, Belgium, ... much easier to find good staves than yew, even in N-France.
2) Every decent hazel bush has a handful of pipe-straight staves from 2 to 10 cm diameter in length and 2 m long. Collect a dozen staves (now is not the best time, actually, even though it is diffuse-porous wood... but at least it less risky than ring-porous species like ash)
3) Hazel is easy wood to work with hand tools (if it isn't spiral grained... many staves are, therefore collect more than one)
4) messing up a few good hazel staves is good practice. Messing up a few good yew staves is a pity...
As for Otzi's bow: a few archery gurus shed their light on whether or not this was a functional bow rather than work in progress:
their conclusion, based on mathematical modelling as well comparison with other bows, indicates that it would break if drawn to a regular length, and would draw 150# at 26".
See
http://www.primitiveways.com/Otzi%27s_bow.htmlIf you need help from a nearby bowyer, I'm only 200 km NW of you :-)
To American standards, I live in your backyard
Joachim