Whitebark pine grows above 8,000 feet in the mountains. Needles are in bundles of five. Cones are purple and shorter than those of limber pine. Aspen grows in stands on level, moist sites and on dry slopes. Aspen bark is smooth and cream-colored.
Reproduction is primarily from shoots sprouting from horizontal roots.
Cottonwoods , close relatives of aspens, grow along rivers and creeks in the valley and lower parts of mountain canyons. Bark on mature trees is heavily furrowed. The species that occur in the park lance leaf cottonwood, narrow leaf cottonwood and balsam poplar hybridize freely, so identification of individual species may be difficult. Common Shrubs Big sagebrush thrives in dry habitats and carpets most of the valley floor. Tiny yellow flowers bloom in August.