The temperature that you get inside a wood burner depends a lot on the type of wood, the dryness of the wood, and how finely divided it is. If you get just the right amount of air underneath, it can get very hot.
My results were always limited when I had too many pine needles or if the wood was damp. Shoot for wood pieces no larger in diameter than a pencil.
The advantage of working with steel or aluminum first is that you can get your design dimensions worked out before you go to titanium. The disadvantage is that it is still a lot of work, and if your metal gets deformed within one or two burns, all of your work goes up in smoke before it can be thoroughly tested.