Hazel=hazelaar=Corylus avellana
Ash=essen=Fraxinus excelsior
Maple=esdoorn=Acer sp.
I've used ash myself, but no hazel or maple (yet). Our European species of maple is not as good as most American species of maple, although our European species of ash is at least as good, probably better, than the American species of ash. Hazel is typically European and is very widespread and abundant here throughout the continent. Easy to work with, takes a lot of abuse and is d*rn difficult to break. But it likes to take set and not an especially good performer. However, if you heattreat the belly, this lousy hazel will turn into a real rocket launcher!
I'm not too fond of European oak...it often disappoints, so it seems. Some oak is really good, while some is really bad. I'm sure it can make nice bows, but it doesn't seem very reliable.
There's plenty of bowwood in Central Europe...just not those species you hear about on the forums, because we don't have mulberry, osage and hickory. Instead, look for yew ("taxus") or "lijsterbes" (Sorbus aucuparia) or elm ("iep").