Depends on what you mean by "mountainous region". If you mean "on a mountain", then you could be right (but then, there's also not going to be any wood to make a fire, so you are going to rely on a gas stove or butane heater). But there's a considerable amount of trees, soil, etc. along the roadside when I drive from Calgary to Golden, and that's going right through the Canadian Rockies. So I'd consider that "a mountainous region".

In the Appalachians, you can be on the top of a mountain and surrounded by trees (which obviously need soil to grow in).