Final answer:
Leopold realized that his perspective on the world was wrong when he saw the greenfire in the wolf's eyes die. This symbolized the importance of living in harmony with nature.
Step-by-step explanation:
At the moment Leopold saw the greenfire in the wolf's eyes die, he realized that the way he was seeing the world was not right. The greenfire symbolized the natural beauty and balance of the environment, and its disappearance made Leopold question his own perspective. This event served as a turning point for him, helping him understand the importance of living in harmony with nature and finding happiness in simpler things.