I was talking with a well known bowyer a few nights ago; someone who makes a very fine line of handcrafted longbows. Like so many bowyers he offers bamboo flooring (plyboo, lamboo, actionboo) as a core material, along with yew.
During our conversation he mentioned to me that he had noticed that straight grained yew used as a core material was producing faster arrow flight in his bows, all things being equal. I found this really interesting, as actionboo is such a popular choice these days.
I own several bows from this particular bowyer. All of them are the same length, two have natural bamboo cores, two have actionboo cores and two have yew cores. All are within two pounds of each other and all have the same string materials.
I do not own a chrono, so this is not meant to be a conclusive test, but I do have a couple of arrows that make a screaming sound when they reach speeds of 170 fps, or greater. I am sure that you know what I mean by this.
The upshot is this; the yew cores are faster by quite a bit, even when some of the bamboo cored bows had a heavier draw weight than the yew cored bows. Aside from the arrow report, I can see the difference too. There is also no noticeable difference in "hand shock" either, which might be expected to be less with the lighter bamboo cores.
Now I am not an arrow speed guy in the least. I am most at home with a fine selfbow as many of you know, and speed is not a selfbow issue as much as it is with glass laminated bows. I just thought that this was an interesting discovery on the part of my friend the bowyer, which my own small time test seems to agree with.
Now what does any of this mean? Maybe it means that in a good bow design a wood core is just as good, and maybe better, than a bamboo/actionboo core, but with so many variables in bow designs, a real conclusion would require real tests, as much as the screaming arrow test appeals to me.