Mountain winds can be pretty fierce, especially in the winter. After only 2+ years the stain on our log siding was noticeablely faded and worse, black mildew appeared in areas on the back/north side of our home.
Gulp, due to the height of the house, we had to hire a crew to spiff it up. They started by power washing the whole thing. That translates into a MESS.....soggy wood pulp everywhere, including on the window screens which was a real pain to remove.