In "The Interlopers" what causes the beech tree to fall over?
Lightning is the cause of the huge beech tree's splitting and crashing over the heads of the two foes, Ulrich von Gradwitz and Georg Znaeym.
At both the beginning and end of Saki's story, it is Nature that acts as the interloper in the feud. First of all, because of the terrible winds, the deer of the forest begin to run when they smell the storm coming. Then, because they know the deer are moving about in the forest, Znaeym and his men venture into the dark forest of Gradwitz.
Just as the foes step from opposite sides of a huge beech tree and glare into each other's eyes, hesitating for only a second, lightning strikes. The sound of massive limbs splitting from the tree can be heard. With limbs falling upon them, the two men are pinioned underneath the "wreckage of splintered branches and broken twigs."
It is in this debilitated condition that the two foes make peace. After cursing each other, the two men gradually find it in their hearts to abandon the feud and reconcile. However, Nature once again intervenes in the feud as ravenous wolves approach.
Ulrich and Georg are roaming the disputed forest on a dark, stormy night. Saki describes a "shriek of the storm" which brings down the tree on top of the two enemies as they stand glaring at one another. So, the tree is felled by lightning, and ironically, the basic subject (a tree from the disputed forest land) traps the men together. They are forced to work with each other, but just as they reconcile their differences, they recognize that their shared fate of death is close at hand with the sound of the wolves.