welcome and keep chucking! mahogany is a soft and light wood, so may be a good one to start. there is a point in light chucks that the wood is so light that it doesn't have the density to cut air and also won't carry momentum[ alot of speed is just adding power momentarily here and there to the momentum to keep speed going]. woodalls at the bottom of the page has neat charts about weight and hardness.
i like yellow heart, purple heart, brazilian cherry[jotoba], bocote for medium+ weight chucks.[light to heaviest i think].
there are many sources of hard and uncommon wood dowels on the internet. perfect for diy projects.
plus wood all looks unique so color and grain varies from piece to piece. look around and see what you like and weigh your chucks and then you can get an idea of what would best suit you.
Well, if you want wood because you are afraid of metal while doing aerials, then you will still be afraid... a good hit with a wooden nunchaku is a very dangerous hit, so still you should fear a wood nunchaku.
You can try PVC nunchaku (DIY) to avoid getting hurt, or you can make a cord nunchaku for practice (http://www.freestyleforum.net/index.php?topic=11619.0)
But if you are careful, and start learning aerials from beginner to expert, knowing well when to get to the next level, you shouldn't have any problems with metal nunchaku
amen be afraid of wood as well!! over the years i have seen KO's[3 times i knocked me out!] to chipped elbow bones!!
