The old tree stump was the bane of Joe's existence for a long time, and, as such, it symbolizes old struggles. The second day Shane comes to the house, Shane helps him uproot it, which, along these lines, signifies the overcoming of an obstacle. But, even though the old problem is gone, it is soon replaced by a new problem. The stump, additionally, symbolizes the power of both men as a team—Joe could not uproot the stump by himself, but in a matter of a day or two he and Shane are able to do it together.
Marian uses this physical symbol to remind Joe how attached he really is to the farm. She also uses it to remind him that Shane will forever be a part of the place. The fence post is juxtaposed to the tree stump—they bookend the text, the stump coming right at the beginning and the fence post coming right at the end. Joe is unable to budge the fence post that Shane put there, demonstrating that there is permanence to Shane's affect on their lives. The fence post also suggests that the Starretts belong there and that no one should move them.
Bob notices how strange it is that Shane does not carry a gun. It is surprising for a man to look so dangerous without even having a gun on him. The gun is attached to the stripping away of manhood. Shane, a real man, does not need to carry a gun. Only at the end does he use or touch his gun, and when he does it is only to do the single thing he thinks is most reprehensible. It is not accidental that the only time Shane uses a gun he does something that he believes reflects so poorly on who he is that it calls into question whether or not he is really a man.