Maybe I've missed it but I've not seen an exhaustive discussion of which species of wood can be used with the bark left on especially after steam or heat gun straightening. I know that blackthorn and hazel do fine and in my experience most maple and oak bark stays on well. Any others you know of that either will or absolutely won't work? And also has anyone attempted to straighten diamond willow. There are a lot of blanks for sale but most look like they would need at least some straightening. I assume that some species are harder to straighten than others.