2021 fire in Tahoe proves forest health makes a difference

The Caldor Fire burned above the enclave of Meyers without burning a single structure in 2021. (Image: Kathryn Reed)

Fuel reduction projects work. That is the conclusion of a study of the Caldor burn area—specifically Christmas Valley and Meyers.

Results of the research by Hugh Safford, a UC Davis forest ecologist, and Saba Saberi, a doctoral student in Safford’s lab at Davis, will be published in the March edition of Forest Ecology and Management.

“More than perhaps any other USFS unit in California, the Lake Tahoe Basin Management Unit has been proactive in reducing fuels and forest density in and adjacent to the (wildland urban interface),” the report states. “… these fuel reduction efforts were widely credited with the ‘miraculous’ events of Aug. 30 and 31, 2021, when not a single structure was lost when the Caldor Fire entered the (Lake Tahoe Basin) at Christmas Valley and Meyers. Firefighters recounted how fire intensities dropped markedly when the fire encountered treated fuels and how fuels conditions on the ground allowed safe and rapid response to ember-generated ignitions.”

The study’s main take-aways about fuel treatments prior to the 2021 Caldor Fire include:

• Trees were three times more likely to survive fire in treated areas; fire severity was mostly lower in treated vs. untreated areas.
• The widespread presence of unburned fuel piles led to higher than expected fire severity and tree mortality in some areas.
• The most effective fuel treatment was multiple entry mechanical and hand thinning plus mastication, without burning.
• Hand thinning and fuel piling followed by pile burning was also an effective treatment.

“Generally, the treatments were very successful at increasing the resistance of forest to wildfire, but the major hiccup at Lake Tahoe is the big backlog of unburned fuel piles,” Safford said in a statement. “The presence of thousands of fuel piles in the Caldor Fire caused higher fire severity than we expected to see.”

Most of the treated areas had been part of the South Shore Fuel Reduction and Healthy Forest Restoration Project, which began in 2012.

Treatments reduce the chances of a crown fire, produce lower intensity fires and flame lengths, and reduce spot fires.

“Overall, our results add the Caldor Fire to the growing list of fuel treatment success stories in the Western U.S., but at the same time highlight the growing urgency of proactive forest and fuel management and the importance of resolving long-standing capacity constraints in the U.S. federal resource management agencies,” the report says.

The study was funded by the Southern Nevada Public Lands Management Act, the League to Save Lake Tahoe, Tahoe Fund, UC Davis and U.S. Forest Service Region 5.

Note: A version of this story first appeared in the Tahoe Mountain News.