The relative hardness of woods is an important part of picking your next stick or baton; however, I would argue equal importance for weight and resistance to damage. Woodworkers, who know everything about wood from a "construction" viewpoint will disagree I think with the following statements, but I'm basing my comments on experience with sticks used as weapons.
Oak is a great bet, but it can be heavy in the hand. If you don't mind extra weight, it's a good all-around stick. Weight sounds great, until you find it slipping out of your hand or rolling loose--but if you're familiar with the weight of oak, you'll be fine.
Hickory is a lighter wood (in weight) than oak, but packs an awfully big wallop. An excellent material if you can find it in a straight length! Can be (but not always) knotty. Also highly resistant to denting.
Sycamore is also excellent, lightweight, and resists damage very well. A sycamore stick will last years, and will bust through anything made of rattan like it wasn't there.
Be careful with maple--not all are hard, and some can even chip quite readily. Rock maple, while popular for a lot of pre-manufactured batons, is light and hard, but can actually fracture readily with a good hit. :grumpy: Some types of maple can be very good, though, but can also be expensive.
With respect to our FMA readers, I do not like rattan. Rattan is inexpensive and flexible--just what the FMA community needs. It's too flexible for me, and every rattan stick I've gone through does a spiral fracture after striking non-rattan sticks. A great material for a Filipino weapon--but you're after hard woods, I believe.
I have no experience with ironwood and will defer to anyone who does.
Cherry is hard, but expensive and won't take abuse for long. :grumpy:
Most woods advertised as hardwoods ("Brazilian hardwood") might actually be composite of hardwood pieces glued together. While strong for general woodwoork, a combat stick made of these will bust apart after even light use. Obviously you'll be looking for something made of SOLID wood. :grumpy:
Obviously, other readers should stay away from softer woods like pine, willow, or balsa! :grumpy:
If you can, go to your nearest big box store. Take a look at the woods they have in stock, such the maple or oak. Obviously, you won't be using a 2 x 6 to make your stick, but you can get a great look at the unfinished nature of the wood. For example, take a look at how much warp there is in the longer boards. Warp suggests a wood that won't hold up well. Does the wood they have in stock have scratches and dings? You've found your local variety might not hold up for long without being dented and mottled. Rub your thumb along the grain. Is it smooth, or can you feel pronounced grain? Too smooth, and it's slippery. Too rough, and your hands will ache.
As I said above, the furniture makes and wood workers will shriek, but the above notes are made from 20 years of watching combat sticks break.
Are you making your own? Lathing it from a larger piece? Salvaging a straight piece from a fallen branch? Let me know--I'm curious about your approach and want to know a little more.
Let me ping FMK on this forum--he handmade his baton from (if I recall) sycamore, and it'll chew through everything.
FMK?