Forests of fir and Engelmann spruce cover the mountainsides in subalpine areas. Outbreaks of spruce beetles have destroyed millions of Engelmann spruce trees. The forests are dominated by lodgepole pine, whitebark pine, subalpine fir, and Engelmann spruce. The Pine Valley Mountains support spruce-fir forests, including a large stand of virgin Engelmann spruce. Whistler hybrid spruce (Sitka spruce and Engelmann spruce). The larvae feed on various conifers, including Engelmann spruce, but mainly "Pinus ponderosa". "Adelges cooleyi" that also infects the Engelmann spruce to complete its lifecycle. There are also occasional Engelmann spruce and blue spruce trees. Other conifer species present are Ponderosa pine, Engelmann spruce, and alpine fir. White spruce and Engelmann spruce are the principal hosts (Wygant and Lejeune 1967). The Engelmann spruce and the subalpine fir are commonly found together. Aspen, Engelmann spruce, subalpine fir trees, and limber pine also grow here. This forest has Engelmann spruce, mountain hemlock, and subalpine fir. Engelmann spruce, subalpine fir, and limber pine. Engelmann spruce, Douglas-fir, and quaking aspen.