Indeed I do use a lot of Rowan (mountain ash). Here are two bows that I made out of Rowan
http://www.primitivearcher.com/smf/index.php/topic,4232.0.htmlThere are a few things that you have to remember though: Rowan is not as good in compression as it is in tension BUT it may fail from the back also. Keep the belly of the bow flat and try to have as much limb working as possible. I personally prefer the gull wing design for Rowan, but the standard D profile is nice also. both profiles are presented in that link of mine.
When selecting Rowan for bows, try to get a nice straight piece that has thick rings. The thicker the better. Ring chasing is hard compared to ash or Osage, because it's hard to see where one ring ends and another begins, but it can be made easier by staining the wood temporarily. I prefer to use the ring I get from underneath the bark, but if it seems thin compared to the other rings I prefer to chase it. A tree that is as thick as your wrist should do just fine.
About drying: I prefer to de bark my tree trunks right away, because they come off nicely when fresh. Then I split the log or shape it to the dimensions of my bow BY THIKNESS. The tapering is best to do later. Cut the width of the bow so that the limb is as wide as the widest spot will be in the bow when finished. A month of drying should do for a roughed out stave. If you want a specific design (for example a Reflex deflex) press the stave to form after roughing it out and then let it dry in form. Rowan holds it's shape best if this in done.
Steam, boiling and dry heat are good for bending the wood to forms such as the recurve form ect.
Oh and one thing still: don't push the wood over it's limits.I would say that 60# is the comfortable poundage maximum for standard sized bows made from Rowan.
And if the bow starts to take set while tillering you can add reflex with dry heat. This will obviously increase the poundage also. And still a bit of something about the dimensions on Rowan bows: I like to make my bows 2.3 times longer than my draw lenght, so a 60" bow would have a 26" draw. Always determin the draw lenght by the lenght of your bow. never do the opposite, except if the bow is longer than needed.