There is evidence that plateau uplifts in the western U.S. (the Colorado Plateau) and Asia (the Himalayan Plateau) have resulted in a general global cooling trend in the past 40 million years. Whatever all the factors were we may never know. We do know that the climate of ancient Florissant was warmer and wetter then. We can see this from the fossil record, which includes Sequoia trees and many types of hardwood trees that today grow in wetter, milder climates. Where do redwood trees grow today? How does geography affect their environment?