This is a great question. First, we should say that the word "fate" is not used in the short story. Therefore, if Saki has an understanding of fate, then it must be deduced from his story.
In my opinion, there is an understanding of fate because both Gerog and Ulrich believe that the other is the interloper. They believe that they could own the stretch of land. They do no consider that their false understanding would be corrected by nature itself. So, when there is a storm, a tree is felled and the men are pinned underneath. In time, they reconcile, but this means nothing, because they are the true interlopers.
At the end of the story, wolves come, and the implication is that the men die. How fitting for men who trespass with no understanding of their hubris.
The point behind this is that fate led them to this place to realize this point. The theme of fate is understated but present.