The Gearhart Mountain Wilderness is part of a continuous, dry, pine forest covering the transition zone. Differences in species are primarily dependent on water availability. The lower slopes tend to be dominated by white fir with a mix of ponderosa pine and lodgepole pines, while the higher elevations are covered with pure stands of lodgepole and whitebark pine. Minor inclusions of sugar pine and incense-cedar can also be found in scattered locations. The meadows scattered throughout the wilderness are characterized by lush, green ground cover, stands of aspen, and a multitude of wildflowers. Riparian zones support tag alder, willow, and a large diversity of understory flora. The Gearhart Mountain Wilderness does have some stands of old growth forest. However, in recent years, a large area of the forest on Gearhart Mountain and surrounding areas have succumbed to the mountain pine beetle, and large dead stands of lodgepole pine can be seen.