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Quaking Aspen, Sleeping Aspen


On a snowshoeing trek in the Absaroka Mountains this weekend, my rather audacious tracks were added to the numerous delicate wildlife trails stitched through a stand of quaking aspen.

Aspen are one of the wonders of our mountain scenery in any season; from the iridescent green of early spring, through the dappled sunlit understory of summer, to glowing gold in autumn, and finally the monochrome of smooth white bark on snowy slopes. A member of the willow family, Populous tremuloides is the most widely distributed tree in North America, and claims the unusual characteristic of existing as a clone: the stands of aspen we see on mountain slopes typically represent one plant, rather than numerous individual trees, and may be centuries old. The plant (or clone) sends up stems as seedlings, which grow into mature trees, age, and die. Yet the clone’s underlying root system persists for much longer than any single aspen tree, and can cover many acres. Aspen clones can be distinguished from one another by characteristics such as leaf size and shape, timing of changes in leaf color, and branching patterns.

Aspens thrive at elevations between 6,000 and 10,000 feet in moist soil and cool temperatures, and require a period of winter dormancy. When golden aspen leaves fall to the forest floor in autumn, this indicates that the plant is gathering its carbohydrate reserves into its root system, where it is stored for the winter. In the spring, the quality and vigor of this stored energy determines the clone’s ability to send up new seedlings, generally at the outer perimeter of the clone.

Stands of quaking aspen provide a valuable source of winter protein and other nutrients for browsing moose, deer, elk, rabbits and beaver. The pruning of aspen by browsing wildlife through this dormant period can help stimulate new growth in the spring, as long it is done at sustainable levels. The next time you marvel at the charcoal-sketched beauty of a wintry aspen stand, watch for signs of wildlife browsing the shoots of young trees along the edges.

-Ellen Vanuga, Wind River Progam Director

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