Tuesday, November 9, 2010

Ecological Systems: Aspen Forests

This widespread ecological system occurs throughout much of the western U.S. and north into Canada, although it is more common in the montane and subalpine zones of the southern and central Rocky Mountains. Aspen forests cover more than three and a half million acres in Colorado, including one patch of over half a million acres blanketing the edges of the White River Plateau and Flat Tops. Many people don't realize that aspen trees form clumps of clones by suckering from underground root systems. Often what appears to be a stand of many trees is actually only one individual tree with many stems. This survival strategy makes aspen well-suited to re-sprouting after large-scale disturbances such as the forest fires that can be so common in some Colorado summers.

Rarity in Aspen Forests

Aspen forests are one of our most species-rich ecosystems. Most of the species that call aspen forests home are relatively abundant and not of significant conservation concern. Rarer species of this system include: purple martin, northern goshawk, Cassin's finch, olive-sided flycatcher, flammulated owl, and dwarf shrew.


Overall, aspen forests in Colorado are in good condition and moderately well conserved. Much of Colorado's aspen forest is owned and managed by the U.S. Forest Service. This system is not as well represented in the nation's Wilderness system as the alpine and spruce-fir ecological systems. Primary human activities in this ecological system include cattle and sheep grazing, recreation, and hunting. Some aspen stands are cut for pulp mills (for the making of composite boards such as plywood). Threats to the aspen forests ecological system are comparatively low. However, in some areas of the state, sudden die-offs of aspen stands have been observed. The cause(s) of this die-off are unclear and research is on-going. Currently, sudden aspen death is not widely distributed across the state, but there is potential for this condition to pose a more significant threat to our aspen forests in the future.

Overall biodiversity, threat, and protection status scores for aspen in Colorado.

A "windrose" graph depicting aspen status for individual scoring factors.

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