Bourne, who joined the merchant group in 1999, will continue to serve the midlands region, but now as regional director.
MacDonald, who has spent three years with the company, and was formerly regional manager for the north, will now become regional director for the north of England and Scotland.
Trudgeon, manager of HSP's Bristol branch and with some 17 years' service, becomes regional director for the west.
He takes over from Eric James who will move to the position of graphics paper director.
The appointments follow the recent defections to rival merchant group Premier Paper of three HSP regional directors, Alan Venn, Andy Thompson and Tony Wood.
Former HSP salesman Andrew Harding has also joined the three at Premier.
They followed former Howard Smith chief executive Martyn Eustace and managing director Fred Haines who left in May for the rival merchant group.
Story by Andy Scott