Final answer:
The metaphor compares Kenneth to a fully grown redwood tree among saplings, highlighting his maturity or prominence compared to his peers, similar to the stature of a redwood amidst younger trees.
Step-by-step explanation:
The metaphor in the sentence "Kenneth stood with his classmates, a fully grown redwood tree among a forest of saplings" suggests that Kenneth is much more mature, taller, or more developed in some aspect compared to his peers, just as a redwood tree is significantly larger and more mature than young sapling trees. This metaphor indicates a difference in stature or capability.
The examples provided from various texts all emphasize the grandeur, strength, and significance of trees, which are commonly used in literature to symbolize individuals of notable presence or achievements in comparison to others around them.