It kind of matters what you want to use the staff for. Different wood has different properties. Incoming wall of text.
Rattan is light and extremely flexible. In my experience, it splinters at the tips from excessive use and is easier to cut, but not so much break. I would recommend this to someone new to staff because potential injuries you can incur upon yourself with it are small. Plus, it's easier for a beginner to enjoy using compared to a heavier wood.
Hickory is very strong and dense. If you buy a walking stick that's supposed to be strong from a magazine, odd's are it's hickory. Hickory is also not uncommon for tools like shovels, axes, or hammers. Personally, I think it would be a bit overkill in weight for a staff. Not that it's weight wouldn't have it's uses. That's only a personal preference. Plus, because of it's density, it can hurt your hands if you hit solid objects too hard. I doubt it would be an issue in martial training. In this context, when I say solid, I mean immovable. All the shock just goes back in your hands. The same is true for any extremely hard wood. But again, that level of shock is unlikely for martial purposes.
I don't know exactly how oak compares to hickory, but it's definitely in the same category.
For training, an overly heavy stick is
great.
I think chinese staffs are made out of palm? And those staffs look pretty flexible.
I really like Ironwood. It's just flexible enough to absorb the shock, really durable (but not quite as durable as hickory), and doesn't scratch or scuff as easily as other woods. And yet, surprisingly light. Not light exactly, but not as heavy as you would expect for it's hardness.
I once read on a forum that "ironwood" was just the local name for whatever the strongest local wood was. Take that how you will. According to that person, the North American version of "ironwood" is called Hornbeam. I can confirm that my "ironwood" is Hornbeam.
Ash was traditional for a lot of spears in Europe. Haven't handled this one, although I've heard it's a mix of flexible and strong. According to
About , British quarterstaffs were made from hazel, ash, oak, or blackthorn.
In my opinion, maple is a lighter hardwood. This could just be that the species of maple I've handled have been lighter. There are a lot of kinds of maple.
Maple is a good example to point out how different the properties of different woods can be. Compared to other hardwoods, maple is lighter. It is very stout. No flexibility at all. However, it can be broken with excessive tension or force. I recommend jo length only as a bo length would be easy to break. It's also easily scuffed.
For a lot of people, maple is a good wood for a walking stick. Light and stout, strong enough, and it can be pretty.
Can't say I've ever handled a Walnut stick. Or heard of anyone trying. I don't know about the properties of Walnut.
The famous Shillelagh is made from Blackthorn. Notoriously heavy and strong. Beautiful too.
There I've heard of sticks being made from other materials. Like hazel, cypress, and sassafrass.
Are you planning on making your own staff or stick? If so, some things to consider.
The longer your stick is, the easier it will be to break. Don't mistake flexibility for weakness. At the same time, don't mistake a lack of it for strength. I don't recommend engravings because they usually splinter easily.
Shape is a complicated thing. Thickness, curvature, taper, whether or not to have grooves for hand grips, whether or not to have a head of some sort, etc. there's a lot that can go into the shape. Some things can be unexpectedly useful. A curve toward the end of a stick for example, can act as a grip and to help your hand stop at the start of the stick and not to slide off. Or, when swinging, wet or weak hands are less likely to lose the staff.
TEST your stick's durability (when it's dry) before putting too much work into it. It's possible that it's rotted, damaged, or structurally unsound in a way you can't see. I have learned this the hard way. At the same time, you don't need to push this too hard. A lesser strength wood that would be a perfectly serviceable stick can be broken. Test it within reason. Don't be fooled by a wood's seemingly impressive strength. It's still wood, and it can still break.
You can kind of feel from striking a surface if it's close to breaking. Just barely. But once it reaches that point, it midas well be broken completely anyway. But not all woods break the same. For example, a maple stick will probably break completely. Hornbeam will have bits of it damaged first before cracking. Rattan seems to splinter in long strips and will not break off completely. Ever. It will only crack and starting splitting a section off of it. Duct tape can keep it running for a long time.

Flexibility helps to reduce the shock that reverberates into your hands from striking things. Flexible wood is usually lighter than harder woods. If you're ever going to use your stick to assist in moving around (canes, "pole vaulting" getting over streams, etc.) you want it to be hard. An overly flexible stick will bend and possibly just crush under your weight.
Some recommend not to peel the bark until after the stick dries. It will be a lot harder to remove the bark, but it is believed to improve the durability.
Mostly, it's just about what you want the stick to do. A lot of wood will do fine. Although, some wouldn't be keen choices. Balsawood like JKS said. I wouldn't recommend or pine or....well, various types of wood I've encountered but haven't been able to identify.

Poplar seems alright. Similar issues to maple.
I also might suggest not putting varnish of any kind on one of your sticks. If you use it often, the oils in your hands will work the stick from your use, and it will become shiny and smooth.
