Core samples from Sequoia affinis fossil stumps preserve annual growth rings that provide clues to past growing conditions in the Florissant valley. The stumps at Florissant have greater average ring width than modern-day redwoods of Northern California, indicating that Colorado's ancient redwoods thrived in more favorable growing conditions than their modern counterparts on the foggy ridges of the California coast. Cone and leaf fossils of Sequoia affinis, though smaller, are most similar to its descendant Sequoia sempervirens, and cellular detail preserved by permineralization reveals similarities in the wood. Together, these factors identify the fossil trees as Sequoia.