I've made alot of arrows from poplar, birch, ramin, and oak dowels. These are by far the most common dowel types available. Note that VERY often, the type of wood is mislabeled on either the bin or the dowel sticker. For a given size, poplar is gererally the weakest shaft, with birch and oak being the stiffest and toughest. To ID, poplar is usually pale yellow (to even greenish) in color has a closed grain. Ramin has fine, porous striations. The grain is difficult to discern from the growth rings. Birch resembles poplar in texture, but is white. Oak, of course, is so common that it's easy to ID.
The biggest challenge to using ordinary dowels is finding arrow quality shafts. Out a typical bin of a couple hundred dowels, I'm lucky if I can find a whole dozen that are straight grained over the entire length, and free of sharp bends, cracks, knots, and other flaws to even consider as arrow shafts. Only "if" you are lucky enough to find more than a dozen, do you have the luxury of trying to loosely spine and weight match them by hand flexing or by lugging your spine testing gear and pocket scales into the store (which I've done). For a given dowel size, the spine range can easily span 50#, and the weight over 100 grains. You can imagine then, the consitency of your groups with arrows made from such shafts.
As a very loose generality, most 5/16" spine in the 40-50# range, and most 3/8" spine 90-100#. Lacking the classic 11/32" size, very few dowels can be found in the highly common 50-60# range, unless you're willing to plane down stiffer 3/8" dowels or scrounge for stiffish 5/16" dowels. If you don't need closely matched shafts, or if you have the patience of running around to several stores to get a closely matched set, dowels are a cheap alternative to commercial shafting. I pretty much only buy dowels for kids arrows, flu-flus, and other random specialty arrows, though, and not for serious shooting.
