This looks like tongue and groove wide plank white oak flooring on the walls. Could be select grade white oak or possibly #1 common. It doesn't appear to have any stain but rather a matte finish polyurethane finish. I typically use a blend of quarter sawn and rift sawn white oak for walls and ceilings because it highlights the grain in the wood. Good luck!

I recently had pine tongue & groove added to my bedroom wall and I would like the finished result to look something like this do you have a suggestion as to what stain color or technique i could use to get this kind of result?