The easiest way is to go up into the attic and check how the roof trusses are positioned. If they run across the wall, it could very well be load-bearing.
NOTE! If you are at all unsure, contact a professional to come and take a look at it.
NOTE! If you are at all unsure, contact a professional to come and take a look at it.
It doesn't have to be. A load-bearing wall, often placed in the middle of the house, often supports the joists to the upper floor, i.e., the floor beams are spliced overlapping over the central wall. In your case, it is the construction of the roof trusses that determines whether the wall can be taken down since you lack an upper floor. Someone who understands trusses could perhaps comment on this if you have a drawing or sketch of how they look. If the wall is load-bearing, it is usually replaced with a beam. In your case, if possible, you could make an opening in the gable and insert the beam there in the attic and anchor the lower arms in the beam. It's a neater solution than having the beam down in the line of sight.
Standing tongue-and-groove planks in this dimension can very well be load-bearing. One of my houses has this construction. If you don't have a wall under this wall in the basement, it is most likely not load-bearing. However, consult a professional to be sure.