Martin Ford chose not to resist a move by Liberal Democrat colleagues to oust him from the joint chairmanship of the Aberdeen city and Aberdeenshire joint strategic planning committee, which drew up the area's structure plan.
Ford said the issue was the subject of internal party procedure. He has been replaced by Peter Argyle, who also succeeds him as Aberdeenshire's infrastructure services committee chairman.
Ford's casting vote saw Aberdeenshire Council reject Trump's plans for two golf courses, lodges and a hotel at Balmedie last November. This prompted ministers to call in the application.