Many of the audience shed tears as Wiremu Edmonds spoke about the loss of his son at the Federation of Maori Authorities' annual meeting on Saturday.
Robert Epapara, the eldest of Mr Edmonds' five children, was killed in a forestry accident near Lake Rotoiti on March 26 last year.
Mr Edmonds, a father of five, has forgiven the man who felled the tree that hit his son, and he has spoken to 63 audiences about the incident since.
He asked the 300-plus audience at the conference to stand up if they were willing to expose unsafe practices and "give absolute commitment to each other".
Mr Epapara was working in a forestry gang when a tree fell on him in Waione Forest.