My garage doors (T&G, braced, side hung, south facing, about 10 years old) are looking tatty, and some of the boards are warped. So much so that the staples have pulled out in places and the evil-minded could get in just by pulling the boards off. They appear to be softwood, possibly untreated before they were finished on the outside with some sort of stain.
The frames are OK, it's just the boards that need replacing. What type of wood would be acceptable, bearing in mind that they have to be stained etc., not painted?