In what ways are Ulrich’s actions influenced by the natural setting and its conditions?

Ulrich von Gradwitz lives for the day that he can rid himself of his enemy, Georg Znaeym, whom he considers a "tireless game snatcher" and "raider of the disputed border forest." Therefore, he patrols this part of the forest regularly. On one particularly windy night as the deer act counter to their natures, he sets out with his foresters to find his enemy, who he determines must be in the forest.

Even during inclement weather, Ulrich has his foresters join him as he patrols the land that he considers his despite the famous lawsuit and the refusal of the dispossessed party not having accepted the judgment of the courts. On this particular night he probably would not venture out, but because the deer have been "running like driven things" rather than bed down in the windy night as they normally would, Ulrich suspects his enemy of prowling this strip of forest. So, he has his foresters station themselves on the crest of a hill while he treks through the lower part of the contested forest.

In the midst of this wind and developing storm, Ulrich comes around a huge beech tree and finds himself staring in the face of his sworn enemy. In that split second of hesitation because of their breeding as gentlemen, neither fires a shot. In the next instant, lightning strikes the huge old tree, and "a deed of Nature's own violence overwhelmed them both." Both Ulrich and Georg Znaeym are pinned beneath splintered branches. 

As they lie trapped together in enmity, each threatens the other with what his men will do to his enemy. But, as time passes and none of the foresters appear, Ulrich begins to ponder their dangerous predicament. After some private deliberation, Ulrich reconsiders, and he rids himself of his animosity. He asks Georg if he can reach his flask of warm wine if he tosses it to Georg, adding, "Let us drink, even if tonight one of us dies. Georg refuses the offer, adamant in his hatred, "....I don't drink wine with an enemy." But, as time passes and Ulrich pursues his attempts at amelioration, Georg finally relents.

"I think I have changed my mind about things, too....And you offered me your wine flask....Ulrich von Gradwitz, I will be your friend."

Like Ulrich, Georg has realized that they are in a life-and-death situation, and a feud over a strip of land somehow seems insignificant now.

Clearly, the stormy night in the forest and their being victimized by Nature has put the enmity that each feels toward the other into different perspectives. Influenced by these factors, Ulrich von Gradwitz offers his friendship to his old foe, and his enemy, George Znaeym, reconsiders his animus and resolves, also, to end their longstanding feud.