gallery Forest Fires Getting Deadlier: Are Pesticides to Blame?

This article can be found in The Green Handbook: Earth + Health page 85.

FOREST FIRES: Are Pesticides Making Them Worse?

Forests are the allies that we need to combat the effects of our current climate crisis. Without forests our days are numbered. Forests and trees filter pollution, reduce air pollutants, and make it easier for us to live. Instead of days of old when forests maintained themselves naturally, today men insist on managing forests. And how do they do it you ask? Why, with chemicals of course!

It blows my mind that nobody is talking about this,’ said James Steidle, a member of the anti-glyphosate group Stop the Spray B.C.”[i]

Researchers from the University of Montana looked at the USDA Forest Service and concluded that in 2010 alone, “1.2 million acres of U.S. federal and tribal wildlands –an area the size of 930,630 football fields was sprayed with 200 tons of herbicides. By far the most commonly used active ingredient was glyphosate –most commonly known to consumers under the brand name Roundup – which is a nonselective herbicide that also kills native grasses and herbs. The U.S. Forest Service, which oversees 193 million acres in the U.S—a quarter of all federal lands declined to share its data on herbicide use. Mike Ielmini, the Forest Service’s National Invasive Species Program Manager, told the researchers that he had concerns about his agency’s data quality.”[ii]

The United States is not alone in practicing chemical forestry. In Canada, forests are also targeted. The Canadian Broadcasting Corporation reported in 2018, “It’s an annual event — a mass extermination of broadleaf trees mandated by the province. The eradication of trees like aspen + birch on regenerating forest stands is meant to make room for more commercially valuable conifer species like pine and Douglas fir. But experts say it also removes one of the best natural defenses we have against wildfire! When aspen and other broadleaves are allowed to flourish, they form “natural fuel breaks” if their leaves are out, according to Lori Daniels, a professor of forest ecology at the University of B.C. That’s why aspen stands are often referred to as “asbestos forests” in wildfire science circles.”[iii]

Bitterroot Wildfire Montana
Bitterroot National Forest, credit John McColgan

Rather than being helpful at all, the use of glyphosate in forests is likely a big factor in the intensity and extent of damage caused by wildfires. As mentioned previously, it’s used to intentionally kill young Aspens and Birch trees and other broadleaf species, trees, which serve as a natural fire wall. If that’s not bad enough, tree health of those remaining is diminished because the herbicides prevent trees and plants from absorbing and holding water, making them dry as matchsticks. From the Sierra Club: “Glyphosate is a patented desiccant. Its desiccating effects reduce a plant’s ability to uptake water. Glyphosate has non-target impacts. Glyphosate use could lead to Sudden Oak Death, Oak Wilt, and a host of Scorch Diseases in which plants can no longer absorb sufficient water and thereby become very flammable. More dry and dead non-target vegetation increases the risk of fire.”[iv] This is devastating news for not only more risk to habitats results, but wild fires contribute vast amounts of the greenhouse gases and air pollutants:  CO2, methane, particulate matter, and nitrous oxide[v]—all crippling climate change instigators. Why are chemicals allowed at all if they can set up forests for failure like this? What people are making these decisions? Back in 2005, whistleblower Doug Parker, who had worked with the USDA Forest Service for over 40 years was fired after reporting misuse of pesticides by Forest Service employees.[vi] Why weren’t the ones misusing pesticides fired instead?

For anyone who’s read Silent Spring, this all may sound like deja vu. As is often seen when humans attempt to manage wild places and wild animals, what may have started out with good intentions almost always results in worsened conditions, or people get too much power that they forget the original aim. Read Sand County Almanac and Playing God in Yellowstone to see what I mean, or read about the USDA’s Wildlife Services–a sick branch of government that shouldn’t even exist. Regarding the forests, Rachel Carson described an awfully similar situation to what we currently have in the West:

“This is what happened in some of the western national forests a few years ago, when in 1956 the United States Forest Service sprayed some 885,000 acres of forested lands with DDT. The intention was to control the spruce budworm, but the following summer it was discovered that a problem worse than the budworm damage had been created. In surveying the forests from the air, vast blighted areas could be seen where the magnificent Douglas firs were turning brown and dropping their needles. In the Helena National Forest and on the western slopes of the Big Belt Mountains, then in other areas of Montana and down into Idaho the forests looked as though they had been scorched.

It was evident that this summer of 1957 had brought the most extensive and spectacular infestation of spider mites in history. Almost all of the sprayed area was affected. Nowhere else was the damage evident. Searching for precedents, the foresters could remember other scourges of spider mites, though less dramatic than this one. There had been similar trouble along the Madison River in Yellowstone Park in 1929, in Colorado 20 years later, and then in New Mexico in 1956. Each of these outbreaks had followed forest spraying with insecticides. (The 1929 spraying, occurring before the DDT era, employed lead arsenate). Chemical pest control in the forest is at best a stopgap measure bringing no real solution, at worst killing the fishes in the forest streams, bringing on plagues of insects, and destroying the natural controls and those we may be trying to introduce.”[vii]

So little has changed. Is the USDA or the chemical industry calling the shots? Is the misuse of herbicides and fungicides also contributing to the spread of tree disease by weakening tree immunity—causing trees to lose their natural resistance to invasive beetles, for instance? Or to white pine blister rust, to aphid infestations, to fungus disease? Is the overuse of these chemicals having an inverse effect by interfering with the beetles’ natural predators, in particular killing off birds? Are the massive amounts of herbicides and fungicides used harming soil quality so far as to make the trees not just unable to absorb water, but unable to absorb nutrients as well? This alone no doubt causes sick trees. Without our meddling, would the forests throughout the west be thriving and more fire-resistant today? Nature is after all very capable of surviving on its own, better usually without human interference. What on earth are we doing to these majestic places and to the animals that dwell within when we keep using these deadly chemicals?


The time has come to stop meddling with forests. Killing chemicals do not help trees, people, animals or ecosystems. We have to stop being conned by the chemical companies whose products are little by little destroying the planet’s health and our own health.

  • Get the pesticides out of our forests before it’s too late!
  • In America urge the USDA Forest Service to cut the use of pesticides in our forest
  • USDA Forest Service
  • 1400 Independence Ave, SW
  • Washington, D.C. 20250-1111
  • Telephone: (800) 832-1355


[i] Bethany Lindsay, “It blows my mind’: How B.C. destroys a key natural wildfire defense every year,” CBC News · Nov 17, 2018,

[ii] Viktoria Wagner, Pedro M. Antunes, Michael Irvine, Cara R. Nelson,  Herbicide usage for invasive non‐native plant management in wildland areas of North America, Journal of Applied Ecology, 29 June 2016,

[iii] (see 464) Bethany Lindsay, It Blows my mind: How B.C. Destroys a Key Natural Wildfire Defense Every Year,” CBC News,

[iv] Sharon Rushton, Ann Spake, Laura Chariton, “The Unintended Consequences of Using Glyphosate”, Sierra Club, January 2016,

[v] Chemical Composition of Wildland Fire Emissions, Shawn P. Urbanski, Wei Min Hao, Stephen Baker,  Developments in Environmental Science, Volume 8, 2009, Elsevier B.V., US Forest Service,

[vi] Dianna Farsetta, Pesticides and Forest Service Fires, The Center for Media and Democracy’s PR Watch, Oct 7, 2005,

[vii] Rachel Carson, Silent Spring, 1962, Houghton Mifflin Harcourt Publishing, USA, p 253

This is our country on Roundup, accounting for agricultural use only. How brown will this map become when public lands, forests, wildlife refuges, grasslands and national parks are accounted for?

Glyphosate Map USGS

As shocking as it may be, this is the green reality.