Give Tahoe Sustainable Solutions: SPF staff thoughts on glyphosate spraying

The edge of the Gondola fire scar - manzanita and white thorn dominate the burn area, small trees emerging

Glyphosate spraying has become a very divisive issue in Tahoe, so we felt compelled to learn about it and form our own opinions as regular citizens and workers in the forest. The Sugar Pine Foundation is not involved in any decision-making or application of glyphosate; this is only a small attempt to summarize our findings on the issue. Our work experience is in planting trees using a shovel and watering them by hand. Through this work we have lots of first-hand observations of the forest coming back after fires in the Tahoe area.

After a fire, the first vegetation that naturally grows back, especially on south- and west-facing slopes, is large amounts of flammable brush — ceanothus (whitethorn), manzanita, chinquapin, etc. This dense fuel load increases the risk of a re-burn and creates favorable growth conditions for highly flammable, invasive annual grasses to colonize the area. North- and east-facing slopes usually burn less and have more native conifer seedlings growing naturally.

The Caldor Fire of 2021 burned almost 222,000 acres, of which about 10,000 acres are in the Tahoe Basin, mainly on National Forest System lands. Because the megafire scorched the natural conifer seedbank in places, reducing the ecosystem's ability to regenerate on its own, there is an urgent need to reforest burn scars, at least along trails and roads. We just had a lightning strike on the sea of whitethorn on Angora Ridge on June 3 that started a small fire. Luckily, firefighters were able to put it out within a day. This will happen a lot more in the future in areas full of head-high brush and fallen burned logs. It's a danger to communities, but also perhaps an opportunity to quickly plant trees after the brush burns.

The Lake Tahoe Basin Management Unit (LTBMU) of the United States Forest Service (USFS) initially addressed the reforestation need by creating the Tahoe Basin Caldor Hazard Tree Fuels Reduction Project. This project focused on removing immediate hazards along trails, roads, and private property, and on identifying priority areas for reforestation, some of which the Sugar Pine Foundation has been working on. The project did not involve the use of herbicides.

Later, the LTBMU conducted a larger environmental analysis, the Caldor Fire Restoration Project, which was completed in March 2026 with the aim of supporting restoration and reforestation of 11,700 acres across the Tahoe Basin. The hazardous and rapidly deteriorating post-fire conditions warranted an Emergency Action Determination, and the LTBMU authorized the use of herbicides on an estimated 2,400 to 3,600 acres where natural forest regeneration drops below 40%. Herbicide is proposed for use in areas where mechanical removal equipment is not permitted, such as steep terrain far from roads, or where the soil or wildlife is too sensitive for machine operation. Herbicide is a cost-effective tool to use before tree planting to manage competing vegetation, since it kills the entire plant it touches. Depending on the species, cutting the shrub is not enough to kill the plant and prevent it from growing back.

Roundup, an herbicide with the active ingredient glyphosate, is the most widely used broad-spectrum synthetic herbicide in the world, primarily in agriculture. It can persist in the environment for days to months, depending on the availability of water around it. It has been classified as a probable human carcinogen by the World Health Organization's International Agency for Research on Cancer. According to a systematic review of the toxic effects of glyphosate on the nervous system published in the International Journal of Molecular Sciences, "exposure to glyphosate or its commercial formulations induces several neurotoxic effects." Glyphosate binds strongly to most soil particles and remains largely biologically inactive there, though its high water solubility can allow it to leach into groundwater. Its rate of biodegradation varies with physio-chemical and biological properties and soil composition, giving it a half-life that ranges from 1 to 280 days. Glyphosate's persistence in vegetation may be only days, but several studies have detected its presence in foods and crops even a year after application.

Environmental organizations such as the Nature Conservancy use glyphosate to control invasive species. They consider it a crucial land management tool, particularly when manual removal is ineffective. Farmers are the biggest users of herbicides and use glyphosate primarily to kill weeds before planting a crop. Applying the chemical saves a lot of manual and machine work; it is highly efficient and very widely used. Even road maintenance organizations spray glyphosate to kill vegetation on both sides of the road, which increases visibility for drivers and reduces the roots that damage the asphalt.

Standing at a modern crossroads, we face choices with profound environmental and public health implications, often compared to the 20th-century struggles over leaded gasoline and DDT. When we choose to be guided by the precautionary principle, which argues for proactive avoidance of chemicals with suspected or unquantifiable environmental and health risks, it acts as a catalyst that galvanizes us to research, design, and implement sustainable, environmentally friendly solutions. Involving local communities in brainstorming ideas to reduce the brush, and indigenous peoples who have stewarded the land, can be widely beneficial. A recent study by UNR, confirmed Washoe understanding of sage brush as nurse plants for pynion pine, not competing vegetation. Let's consider options such as hand crews, naturally occurring herbicides, masticating the brush, using animals to graze it, or simply letting ecological succession take its course in areas not directly adjacent to communities. The forest belongs to all of us, so its stewardship should be shared collectively.

This might result in goals being scaled back and the forest coming back more slowly than expected, but it will be free of toxins. It may also result in cheatgrass and other invasive species proliferating in some areas. Reforestation isn't merely planting trees; it demands the careful restoration of the entire native ecosystem to provide life-sustaining habitats and food sources for wildlife. If we want to ensure these native landscapes heal, it will require intentional, sustainable solutions. Our voices against synthetic pesticides should not be mere echoes in Tahoe — they should turn into a ripple effect throughout the country, as roughly 300 million pounds of glyphosate are used in U.S. agriculture and infrastructure annually.