What type of sander will sand a piece of flat rough wood the quickest?

A belt sander is typically the fastest option for sanding a piece of flat, rough wood. It uses a continuous loop of sandpaper, allowing it to remove material quickly and efficiently from large surfaces. For finer finishing, a random orbital sander can be used after the belt sander to achieve a smoother surface. However, for initial heavy sanding, the belt sander is the best choice.