STATELINE, Nev. — The debate over how to restore forests burned by the 2021 Caldor Fire reached a boiling point this week as more than 100 people gathered, in person and online, for a Tahoe Regional Planning Agency meeting focused on a controversial proposal to use glyphosate and other herbicides in the Lake Tahoe Basin.
The Aug. 26 meeting of the TRPA Environmental Improvement Program committee drew a crowd large enough to exceed the meeting room’s capacity. More than 50 people reportedly addressed the committee during public comment, with opposition centered on the U.S. Forest Service’s Lake Tahoe Basin Management Unit Caldor Fire Restoration Project.
The controversy has particular significance for El Dorado County residents. The Caldor Fire began in El Dorado County in August 2021 before burning more than 220,000 acres across El Dorado and Amador counties and eventually entering the Lake Tahoe Basin. The fire forced evacuations along the Highway 50 corridor and in the Tahoe Basin and left a vast landscape requiring long-term restoration.
A massive restoration effort
The Forest Service says the Lake Tahoe Basin restoration project encompasses approximately 11,700 acres of national forest land affected by the Caldor Fire.
The agency’s proposed work includes removal of fire-killed and damaged trees, forest thinning, preparation for planting native seedlings, prescribed fire, stream and meadow restoration, wildlife habitat improvements and other measures intended to rebuild forest resilience.
Herbicides are one tool included in that restoration strategy. The Forest Service has said approved herbicides could be used to help prepare planting sites and control competing vegetation that could interfere with the establishment of young trees.
Forest Supervisor Erick Walker has argued that intervention is necessary because portions of the burned landscape could otherwise take decades to recover.
“Without assistance, the Caldor Fire area could take decades to recover,” Walker said when the Forest Service announced the restoration proposal.
The Forest Service has emphasized that herbicide use would not involve aerial spraying. Under the proposal, trained crews would apply herbicides with backpack sprayers, with restrictions designed to reduce the possibility of chemicals reaching waterways. Those restrictions include maintaining buffers from water bodies and avoiding applications ahead of significant rainfall.
Water quality at the center of the dispute
For opponents, however, the issue is not simply how herbicides would be applied. It is whether synthetic herbicides should be used at all in a watershed surrounding one of the nation’s most closely watched alpine lakes.
Lake Tahoe’s watershed is designated an Outstanding National Resource under the federal Clean Water Act, and concerns about protecting the lake’s renowned clarity have intensified the debate.
TRPA Executive Director Julie Regan said earlier this year that the agency wanted closer coordination with the Forest Service and water-quality regulators before site-specific restoration work involving herbicides proceeds.
“We’ve sent a formal letter to the forest service requesting coordination with TRPA, the Lahontan Regional Water Quality Control Board, and others to protect the lake’s water quality,” Regan said.
TRPA also indicated that it was expanding water-quality monitoring, including testing for glyphosate downstream from portions of the Caldor Fire burn area.
Glyphosate remains a flashpoint
Glyphosate, the active ingredient in many widely used weed-control products, has become the central flashpoint in the Tahoe restoration debate.
Its safety has been the subject of competing scientific and regulatory conclusions. The U.S. Environmental Protection Agency has determined that glyphosate is not likely to be carcinogenic to humans when used according to its label, while the World Health Organization’s International Agency for Research on Cancer has classified glyphosate as “probably carcinogenic to humans.”
That disagreement has done little to calm Tahoe residents who believe the risks are unacceptable in the Lake Tahoe watershed.
Environmental organization Keep Tahoe Blue has called for herbicides to be used only as a last resort and urged the Forest Service to prioritize other restoration techniques. The organization has also called for strict safeguards, scientific monitoring and public notification if herbicides are ultimately used.
A debate that reaches beyond Tahoe
The dispute reflects a larger question facing communities throughout the Sierra Nevada: How aggressively should land managers intervene after catastrophic wildfire?
The Caldor Fire provides a particularly complicated case. Its burn scar crosses multiple jurisdictions and landscapes, including portions of the Eldorado National Forest outside the Tahoe Basin.
The Eldorado National Forest has separately moved ahead with its own Caldor Fire Restoration Project. In March 2025, Forest Supervisor David Fournier signed a decision for Phase I of that project, which includes mechanical fuel reduction, prescribed burning and infrastructure repair. The Forest Service said the work is intended to reduce public-safety risks and improve forest resilience.
For El Dorado County, the distinction matters. Restoration decisions made on the western slope and in the Tahoe Basin involve different management units, but they are part of the broader effort to recover from the same 2021 disaster.
The El Dorado County Resource Conservation District has described the Caldor Fire as a 221,775-acre disaster that affected El Dorado and Amador counties, with extensive damage to communities, forests and infrastructure. Its restoration work has included hazardous-tree removal and assistance to landowners rebuilding after the fire.
The question now is what comes next
Wednesday’s meeting did not end the debate.
Instead, it demonstrated how intensely residents are watching the Forest Service’s restoration decisions — particularly when those decisions involve chemical treatments in a watershed shared by California and Nevada.
The Forest Service maintains that herbicides are one component of a broader restoration program designed to re-establish forest cover, reduce wildfire risks and improve ecosystem health. Opponents argue that Tahoe’s unique environmental value warrants a much higher threshold before synthetic herbicides are introduced.
For communities in El Dorado County that lived through the Caldor Fire, the disagreement is more than an environmental policy dispute. It is part of the continuing struggle over how the Sierra should recover from a fire that permanently changed the landscape from Pollock Pines and Grizzly Flats to South Lake Tahoe.
The question is no longer whether the Caldor Fire changed the forest.
It is who gets to decide what the forest becomes next — and how much intervention is too much.
Sources: U.S. Forest Service, Tahoe Regional Planning Agency, Tahoe Daily Tribune, KUNR Public Radio, Keep Tahoe Blue and El Dorado County Resource Conservation District.
