Justification for Alcoa's exemption order regarding black cockatoo habitat tree diameter thresholds.

“What justification can the minister provide for the decision to make the diameter threshold for significant trees for black cockatoos at Huntly mine 1,500 millimetres for marri and 2,000 millimetres for jarrah, noting that these thresholds are significantly higher than the 500 millimetres referred to on page 28 of the document referred to above?”