My main concern regarding these tests is anchoring. If you clamp a spear to two surfaces, then cut in between them it isn't going to behave like a help spear at all, and the same applies to a much larger extent to shorter one handed weapons. In any case, the capacity to cut them certainly exists to some extent (after all, axes are used to take down entire trees), the question is really just one of how much abuse it is going to take to get through various wooden shafts.