Autumn aspen trees near Guardsman Pass, Utah, United States

Autumn aspen trees near Guardsman Pass, Utah, United States

What makes a tree 'quake?' Take a closer look at an aspen leaf. Its flattened stalk catches even a light breeze, making the leaves flutter and giving the tree its name: quaking aspen. Near Guardsman Pass in Utah, United States, these trees form striking groves across the higher mountain slopes, where cooler, moist conditions suit them well.

Quaking aspen is Utah's state tree and one of the state's most common forest types. It grows mainly at higher elevations, often alongside spruce and fir, and spreads through root sprouts. This means a grove can contain many stems connected to one root system, forming a genetically identical clone. In autumn, the leaves turn shades of yellow and orange before falling.

Aspen has practical uses too. Its light, soft wood is used for lumber, pallets, crates, pulp and matches. The trees also provide food and shelter for wildlife, protect soils and watersheds and offer forage for animals such as elk and deer. At Guardsman Pass, their seasonal colour is a reminder that these trees are useful long after the leaves have changed.