I am exposing the post and beams in the upstairs and I came across this post. Its 4x4 and i believe it was put in to give the plaster guys something to nail the lath on too. Can it be removed? Im worried it may have the sheathing attached to it on the outside. I have no real way to determine if it is or not. It is the beam in the middle. It looks like it is supporting the brace but the brace is in prefect shape so it should need any support.

Heres the pic (Hopefully)

that is called a "stud" and yes, the sheathing is likely nailed to it.

Its a 1830 post and beam house. The posts and beams are made of Chestnut and the "stud" is from pine. There are no seams of the sheathing on the "stud". The gap from Post to Post is 36 inches. I don't see why it couldnt be removed. Its not a structural Stud like in conventional building. There is a 1/4 gap of air between the corner brace and the "stud"

I believe this post is acting as a lateral bracing for the opposite wall.I would not remove it without adding more lumber and a simpson plate strapping