Visiting a marae (Maori meeting ground) begins with a highly symbolic welcome ceremony. As part of that, a young man of the iwi (tribal group) to which the marae belongs will issue a challenge (wero) to the visiting party.
The challenge involves a symbolic demonstration of the iwi’s fighting prowess in the form of the young man and his weapon. It is asking the visitors “do you come here with peaceful intentions?”
A representative of the visiting group (usually a man) accepts the challenge by picking up the taki — a symbolic object which in many cases is a branch (think olive branch in terms of symbolism).
After that the group is welcomed onto the marae.
You can find out more about this powhiri (welcome process) here.