Common Trees Most of the trees in the park are conifers because of the short growing season. Deciduous trees shed their leaves in the fall and must grow new ones each spring before they can photosynthesize. Aspens and cottonwoods have chlorophyll in the bark and so can photosynthesize before produc-ing leaves. Lodgepole pine , the most obvious and abundant conifer in the park and parkway, grows on the lower slopes of the Tetons and on well-drained glacial soils throughout the valley. Large diameter trees have coarse, furrowed bark.
Subalpine fir occurs on wetter north-facing valley sites and at higher elevations in the mountains.
Smooth bark and spire-like growth form identify subalpine fir. Needles occur singly and feel soft. Cones grow upright on branches. Engelmann spruce occurs with subalpine fir, especially along creeks in the canyons between Teton peaks. Rough bark and abundant cones hanging down from upper branches identify Engelmann spruce.