Reducing the fire threat: Mechanical thinning now allowed along Lake Tahoe's steep slopes

Forest thinning projects in the Lake Tahoe Basin just got a new partner that will help remove the threat of wildfires in a cheaper and more efficient manner.

The Tahoe Regional Planning Agency Governing Board unanimously approved a change to its policy that will now allow mechanical thinning on slopes with a 30-50 percent grade. Prior to today's action, it was only allowed on slopes under a 30 percent grade and anything steeper had to be done by hand crews, pile burning, and aerial logging to protect water quality from potential erosion.

“The Caldor Fire and the surge of megafires in the region are clear directives for us to improve our forest health policies to better protect communities and the environment from wildfire,” TRPA Executive Director Joanne S. Marchetta said. “TRPA is committed to advancing science-based practices that protect the lake and bolster our resilience to ever-growing wildfire threats, especially given the need for fuels reduction work in untreated areas narrowly missed by the Caldor Fire.”

This new policy change opens up approximately 61,000 acres in the Lake Tahoe Basin that can now be treated mechanically. Nearly half of that area is in wildland-urban interface defense and threat zones near communities where hand crews continue to work.

During the Caldo Fire, the post-fire assessment showed steeper slopes tended to burn at higher severity than other areas.

“This is a game-changer for fuels reduction in the basin,” said Chief Scott Lindgren of Tahoe Douglas Fire Protection District. “Hilly terrain is a significant portion of the Tahoe Basin and with the right kind of equipment, we can do quality fuel reduction work and protect the environment at the same time.”

The use of mechanical equipment on steep slopes used to create impacts to soil and the watershed, but research now shows the new equipment is lighter and can sometimes cause less of an impact than hand crews. The recent research was in partnership with USFS Forest Service Pacific Southwest Research Station and the University of Idaho and also showed the new policy would increase forest and ecosystem resilience to disturbances such as fire, insects and disease, and climate change.

“The Forest Service and our partners have made great strides toward increasing the pace and scale of forest health treatments in Lake Tahoe forests, but there is much more work to be done,” said Forest Supervisor, Erick Walker. “By exploring new ideas and expanding treatment methods in challenging areas, we can provide land managers with more effective tools to help restore forests and increase landscape resilience. TRPA’s amendment allows the Forest Service to consider the use of equipment on steeper slopes when and where appropriate, to treat and remove forest fuels where the only option had been to hand thin, pile, and burn.”

“Mechanical thinning can be a much more efficient and effective option when used in suitable locations, especially when hand crew capacity is a limiting factor,” Walker added. “This change will help increase the pace and scale of forest restoration to meet the goals of the Lake Tahoe Basin’s Multi-Jurisdictional Fuels Strategy and would contribute to Forest Service efforts to advance forest health in collaboration with partners nationwide through our newly launched 10-year strategy, Confronting the Wildfire Crisis: A Strategy for Protecting Communities and Improving Resilience in America’s Forests.”