Why is the Forest Service using glyphosate in our national forests?

The Forest Service stewards land that provides sanctuary for wildlife and opportunities for people to connect with nature. 

Why then is the agency spraying a potentially carcinogenic herbicide on clear-cut and fire-ravaged national forests in California?

A recent article published by Mother Jones delved into these questions, examining the extent to which glyphosate-based herbicides are used in the national forest near Lassen Volcanic National Park. 

What is glyphosate?

Discovered in 1950 by a Swiss chemist named Henri Martin, glyphosate is the most widely used herbicide in the United States, having been used to treat between 13 and 20 million acres annually in recent years according to the Environmental Protection Agency. 

To put this into perspective, the amount of glyphosate sprayed annually is equal to an area roughly the size of Texas, Kansas and Wyoming combined.

Twenty years after the discovery of glyphosate in the 1970s, a chemist employed by agricultural giant Monsanto discovered its herbicidal properties, thus creating the infamous weed whacker: Roundup. 

Roundup and other glyphosate-based herbicides are widely used for eliminating weeds and grasses. Glyphosate is also sold in various forms, including concentrated liquid, solid, and “ready-to-use liquid.”

Monsanto’s invention of “Roundup-­ready” crops in the 1990s led to an increase in use.  These genetically modified corn and soybeans were more tolerant to glyphosate, so farmers were able to kill unwanted vegetation in their fields in one swift spray, while their corn and soybeans continued to grow.

Is glyphosate harmful?

For years, the pesticide industry has defended glyphosate use. But recently a scientific study concluding that the herbicide is safe was retracted because Monsanto was found to have had significant influence on the study.

In March 2015, the International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans.” There is also evidence that suggests glyphosate could contribute to ailments besides cancer, from brain inflammation to metabolic and liver problems in children. 

When it comes to wildlife, a 2020 EPA report noted that glyphosate injures or kills 93% of endangered species and 96% of their critical habitat.

What is the current status of glyphosate?

Discourse around glyphosate has helped raise public awareness about the chemical’s potential health risks. The EPA is currently re-evaluating the environmental risks associated with glyphosate after a federal appeals court determined that the EPA’s health assessment did not adequately consider whether the herbicide is carcinogenic. 

While Americans wait for the EPA’s decision, thousands have taken legal action against the producers of Roundup, claiming the chemical is responsible for making them sick. Bayer (the company that acquired Monsanto in 2018) has spent at least $10 billion on settlements and jury awards from around 100,000 cases to date. 

Bayer phased out glyphosate in their consumer-facing Roundup products in 2023. However, they still sell industrial glyphosate-based herbicides to licensed applicators.  

Why are we using glyphosate on federal public land?

Glyphosate isn’t just being utilized by farmers; it is also used by the Forest Service. 

Following a controlled burn or clear-cut, the areas are sprayed to help regenerate conifer growths, which are logged for profit. Once new baby pines are planted, US Forest Service workers apply glyphosate with portable backpack sprayers to terminate the growth of deciduous trees, native shrubs, and flowering plants, all of which compete with conifers for resources (i.e., water, nutrients, and sunlight). The wax-coated needles of conifer trees protect their sensitive tissues from herbicide exposure, allowing them to continue to grow despite glyphosate exposure. 

According to the Mother Jones investigation, 266,000 pounds of pure glyphosate was sprayed in California state forests in 2023. Their analysis shows that is, approximately five times what it was in the early 2000’s when glyphosate-based herbicides were popularized. According to Mother Jones reporter Nate Halverson, the Forest Service notified nearby residents that they plan to spray glyphosate starting in Spring 2026 on 10,000 acres of land near Lassen Volcanic National Park. 

This type of treatment might make the forest more susceptible to wildfires. Deciduous hardwoods can actually slow down a fire. Conifers, on the other hand, are more flammable. A densely packed conifer forest could be more prone to faster moving fire. Fire is part of a forest’s natural cycle. Manicuring wild forests with glyphosate to make them more economically viable disrupts the natural balance, potentially harming humans and wildlife. 

What should we do about glyphosate in our forests?

1. Only California and Arizona have mandatory reporting for pesticide usage. This means that if there is spraying in other states, it’s likely not being reported. Other states should adopt mandatory reporting.

2. Forests should generally be allowed to grow back naturally after a fire. Forest ecosystems are supposed to evolve in decades-long cycles and we should usually let nature run its course.

3. If management is necessary for the ecological health of the forest, the Forest Service should default to using workers, tools and machines rather than herbicides. 

4. The Environmental Protection Agency should enact a moratorium on the use of glyphosate until and unless it’s proven to be safe by publicly funded studies.