Aspen Community Restoration

Red-breasted Sapsucker perches on an aspen trunk Photo Credit: Will Richardson.

Historical aspen tree carving from basque sheep herders.

Conifer Removal During Aspen Community Restoration Project.

Dusty Flycatcher Nests in an Aspen Photo Credit: Will Richardson

Why is the Aspen Community Restoration Project so Important?

Did you know that the Quaking Aspen or Populus tremuloides is one of the largest living organisms on earth?

Aspens are not only astounding in their size but are a vital part of the ecosystem, especially here in the Lake Tahoe Basin. The Aspen Community Restoration Project originated from the Lake Tahoe Watershed Assessment (USDA 2000) which identified aspen stands as Ecologically Significant Areas. They earned this status because of their high ecological value yet relative scarcity on the landscape. Aspen represent less than 2% of the land managed by the Lake Tahoe Basin Management Unit yet, this forest type has tremendous value for wildlife, soil processes, scenic integrity, and viewing opportunities. They are also of historical value, aspen carvings on trees located in the Basin represent over a century of history about past cultures in the area.

What Have We Accomplished?

From 2009 to 2017, we have removed conifer trees nearly 500 acres of aspen throughout the Lake Tahoe Basin! Although conifer trees are a natural part of aspen ecosystems, without disturbances like fire, these conifer trees grow so numerous that they outcompete aspen for light, growing space, and nutrients. Before long, the aspen are replaced by conifer trees.

How have Aspen Forests Changed with our Restoration?

Aspen Stand Before

Aspen stand before treatment

Aspen Stand After

Aspen stand after treatment

What has monitoring shown us?

Aspen response (partner Pascal Berrill and Christa Dagley of Humboldt State University)

Aspen tree regeneration is increasing at sites that have had conifers thinned but decreasing at sites that haven’t had treatments.
Conifer trees are still abundant in aspen stands, even at treated sites.
- Restoration success would be improved by continuing to cut the small conifers growing in the understory AND removing the larger conifer trees (greater than 30 inches in diameter). Conifers take 18-22 years to reach 4.5 feet in height but aspen can take only 4 years to reach this same height. Large conifers are the seed trees that produce all of the smaller conifers. These are also the taller trees shading out the older aspen in the upper and lower canopy levels.
Burning piles leaves blackened patches of ground. After 2‐4 years, herbaceous cover in burn patches was 35‐71% of that adjacent to burned piles.
Aspen are more likely to regenerate inside burn scars where fewer of the surrounding trees are firs.

Bird response (partner Will Richardson with Tahoe Institute for Natural Science)

The disturbance of removing conifers doesn’t appear to have immediate negative effects on the bird communities.
All restored sites had a high volume of bird activity immediately following treatments and in later surveys.
Mean bird abundance and bird species richness increased with treatment.

What more do we hope to accomplish?

Restore more aspen stands throughout the Lake Tahoe Basin.
Remove more conifers from previously treated aspen stands to prolong aspen persistence in the canopy and forest floor.
Use prescribed fires in treated aspen stands.

Who are our partners?