A Massive Investigation Just Exposed How Much Roundup Is Being Sprayed in Northern California’s Forests

A yearlong investigation by Mother Jones has shed new light on the scale of glyphosate spraying across California’s forests, and the findings are raising serious questions for anyone who hikes, camps, forages or recreates on public land in Northern California.

According to the investigation, which analyzed more than 5 million state pesticide records, the amount of glyphosate applied in California forests reached 266,000 pounds in 2023. That is nearly five times the amount used two decades ago, making forest applications the fastest-growing market for the herbicide in the state.

The Forest Service is now planning to go even further. The agency has approved spraying on roughly 10,000 acres of the Lassen National Forest, where the Dixie and Park fires burned hundreds of thousands of acres. It also plans to treat up to 75,000 acres affected by the 2021 Caldor Fire, including areas near the base and parking lot at Sierra-at-Tahoe and forests close to Kirkwood and Heavenly ski resorts. The plans include spraying in campgrounds, around trailheads and near homes in Meyers. The Pacific Crest Trail runs directly through some of the most heavily treated areas.

The herbicide, best known by the brand name Roundup, is used to kill shrubs, flowering plants and hardwood trees that compete with replanted conifers after fires and logging. The World Health Organization’s cancer agency has classified glyphosate as a probable carcinogen, and manufacturer Bayer has paid more than $12 billion in legal settlements to people who say the product made them sick.

The investigation also found that the Forest Service’s own safety assessment relied heavily on a study that has since been retracted after it was revealed to have been ghostwritten by Monsanto employees.

The full investigation is available at motherjones.com.