Just read a member's post where he said that he was selling african driftwood, the kind that doesn't rot.... is it known that African driftwood rots more than other types of driftwood?
African wood can rot as easily or last as long as American or European wood. It's not the continent of origin, it's the tree species and process of "conservation/natural treatment" you should inquire about. A seller should be able to give you these details.
FWIW: I always harvest my own driftwood. That way I know exactly where it's from and I can be sure that it meets or exceeds my own requirements for my tank.