Cr Birchfield, who will make $83,500 a year, will be assisted by deputy Stewart Challenger.
Cr Birchfield, whose strident views on climate change and the environmental lobby have previously gained wide attention, told councillors on Friday this term would probably be his last.
He was a good advocate for industry, but was well aware of the difference in being a councillor, and chairman.
"As a chairman I will represent the council and consider everybody's views."
Cr Magner, in her first term, discussed the values required as chair.
In the present, challenging environment she would present the views of the whole council. She stressed her calm manner, agile mind and other leadership positions.
She would ensure effective and open dialogue with Government and have an inclusive style of business.
"I will be a strong advocate for West Coast business."
Cr Birchfield, nominated by Cr Peter Ewen, was elected and after a further vote, Cr Challenger was picked as deputy chairman.
Regular councillors were told they would take home $35,733.
