Leopold saw through the rings of the good oak, and realized that humankind's conflicts are arbitrary from the perspective of nature. The good oak adds a layer that describes chronological time: past, present and the future. The tree goes through cycles of seasonal changes; and these repeated cycles results in the oak's rings: one ring for each year.
Explanation:
Leopold's good oak educated people about land ethics and the cycling of matter and energy through an ecosystem in predator-prey relationship.
