In the fall, while the conifers are preparing for the long, cold winter to come, the leaves of the deciduous trees of the Tetons begin to change color. Along river corridors and in wetlands, the leaves of the narrow-leaf cottonwoods and balsam poplar turn a golden yellow. These trees thrive in the changing water levels that come with the Teton seasons. Large hillside stands of Quaking Aspens change from bright green to yellow and orange. These trees, connected under the ground by spreading root systems, are all one organism, and therefore all change color at the same time! Many species of willow provide food and cover for moose, sandhill cranes and other wetland inhabitants. Big sagebrush and low sagebrush cover most of the central valley and grow well in water-deficient soil. Although sagebrush is only eaten primarily by pronghorn and sage grouse, these hearty shrubs provide essential habitat by creating shelter from the wind, rain and snow that blows across the flats.