For some tribes, the ones where both women and men wore their hair long, cutting it was often done in mourning a dead loved one.

Women of various tribes would either cut or let their hair grow longer in a display of marital status. In some plains tribes and most of the eastern woodlands a warrior would pluck or shave the majority or part of his head into a scalp lock as a challenge for an enemy to come take his scalp.

The concept that all Indians wore/wear their hair long is a fallacy.

Sorry I could not answer your question the way you wanted me to.