To me the mountains look like a granite pattern that was then bumped (layer of 50% gray set to overlay then use the dodge tool for brighter/higher spot and the burn tool for darker/lower spots) with some red airbrushing in places. The lake is, as RobA said, a distort filter with a lil extra bumping or plain old airbrushing. The forests look like a textured bevel or a lighting effects applied to many renditions of difference clouds with some rusty spots thrown in to break up the color. The grass looks like a lighting effects applied to some clouds with added noise and then inner beveled around the water or possibly bumped because there are some subtle hills. Looking at it some more the grass could just be a textured bevel as well...not sure what the pattern is but something like blurred blobs.