Bristlecones are the oldest living tree, having been dated to over 4000 years old. This took place most recently by glaciers about 10,000 years ago. The climate and the weather determine many of the features that you see today. The forest of solid evergreens that extends from about 9000' to about 11,500' feet in Colorado. The forest ends where the Alpine tundra begins.
Tundra is a Russian word.
The alpine tundra may look barren but grasses, sedges, lichens and many species of wildflowers manage to survive here, even though the growing season is very short. Where the forest ends and the Alpine tundra begins. They are the last evergreens to grow at the edge of the tundra. These bent crooked trees may look like shrubs, but can be hundreds of years old. They can be englemann spruce or sub alpine fir.