Collaborative Forest Landscape Restoration Program Success Story

Southwestern Crown of the Continent – Aspen Restoration

Firefighters using prescribed fire to stimulate aspen restoration.
The Southwestern Crown Collaborative helped accomplish 3,908 acres of reforestation and revegetation in FY 2011, including the aspen restoration shown above.

Among the numerous restoration activities undertaken by the Southwestern Crown Collaborative (SWCC) as part of the CFLR program was restoration of aspen trees along the Alice Creek Road in the fall of 2011. While not often in the forefront of discussions about ecological restoration, aspen trees are a crucial part of the Southwestern Crown landscape. As one of the few broad-leaved deciduous trees in a mostly evergreen forest, they provide unique forage opportunities for wildlife, such as elk, and they support a higher diversity of bird species than surrounding conifer forests.

Aspen trees are currently in decline across the West, including in the Southwestern Crown. They are a fire-dependent species, and a history of fire exclusion has hindered their ability to reproduce and has allowed coniferous trees, such as Douglas-fir and lodgepole pine, to crowd them out. Aspen reproduce primarily through suckering/sprouting from root systems, as opposed to spreading seeds. In fact, what looks like a stand of aspen trees are actually clones that are one organism. A clone of aspen can live hundreds or even thousands of years.

Fire will often kill individual aspen stems, and this stimulates the clone to create suckers or new shoots to sprout. Fire also cleans out the grasses, forbs, shrubs, and conifer trees that grow up among the aspen, thus giving them the sunlight and space they need to thrive. This is how aspen trees continue to stay vigorous and healthy and maintain their presence on the landscape. As many as 50,000 to 100,000 suckers can sprout and grow on a single acre after a fire.

While aspen are currently faring better in the Southwestern Crown than in other western landscapes, without intervention aspen in the Southwestern Crown are at risk of continued decline. A healthy aspen grove includes sprouts, saplings or middle-aged/sized trees, and mature trees. The absence of young shoots and saplings, coupled with the presence of conifers intermixed with mature aspen, is a sign that replacement of the aspen grove may be underway. The key to maintaining a healthy aspen grove is a continuing source of sprouts.

The Lincoln Ranger District’s efforts in Alice Creek include approximately 75 acres with three large mature aspen stands mixed with mature and dead or dying lodgepole pine infested with mountain pine beetle, as well as some subalpine fir and Engelmann spruce. The aspen clones in these three stands are old/decadent and not currently suckering on their own. The District’s goals with this project were 1) to reduce the pine, fir, and spruce encroachment in and adjacent to these clones to reduce the competition to aspen and allow for aspen expansion, 2) to stimulate suckering and expand these aspen clones over a larger area, and 3) to promote multiple age and size classes.

To achieve these goals, the local Forest Service fire crew used chainsaws to cut, slash/scatter, and hand-pile 60 to 90% of the lodge-pole pine, fir, and spruce in these three stands. Some of this material was also used to create a fuel bed. At the edges of these clones, slash was arranged as a barrier to cows where feasible. The hand-piles will likely be burned in 2012. These stands may also be burned using prescribed fire in order to kill the aspen stems, promote suckering, and clean up residual slash.

Please direct any questions to Lauren Marshall (lemarshall@fs.fed.us).