A controversial study aimed at one of the nation's largest timber companies has raised questions about the overall effects on wildlife, and possibly human health, from the industry's use of pesticides.
While the study by the San Francisco-based environmental group ForestEthics focused on Sierra Pacific Industries and the more than 1.7 million acres it owns in California, environmentalists say the group's analysis raises concerns about the land management practices of the timber industry overall.
"It would be safe to say there's a disturbing trend of herbicide use in the timber industry nationwide," said Josh Buswell, Sierra campaigner with ForestEthics. "If Sierra Pacific Industries is any indication, other companies in other states are probably using them extensively, too."
The study analyzed a massive state database on pesticide use between 1995 and 2007 and claimed that Sierra Pacific Industries -- the nation's second-largest private landowner -- used herbicides on its tree farms in California more often than it admitted.
The environmental group claims the company's use of herbicides to promote growth in its Northern California tree farms could have a wide range of detrimental effects, especially on wildlife -- a charge they say is substantiated by numerous studies showing harm caused by the chemicals. The group also warns that these herbicides could be hurting the people who spray them as well as the people who drink water originating from sources that are polluted with the chemicals.
The timber industry bristles at suggestions that it is saturating land and waterways with potentially dangerous herbicides, insisting that state and federal laws place tight clamps on how much is used and how they are applied. Sierra Pacific officials and other industry representatives say herbicides are only applied after a tree farm has been clear-cut and harvested, which is only a few times every 80 years or so.
"Chemicals used by the industry are approved and highly regulated by the U.S. EPA after extensive safety analysis," said Scott Milburn, a spokesman for the American Forest & Paper Association, the industry trade group in Washington, D.C. "Our companies rely on a fertile environment for their livelihoods, so they take sustainability very seriously. It is right for the public and activists to pay close attention to chemical use. We do, too, and we welcome fair scrutiny, but we also encourage it to be applied with a dose of perspective, sound judgment and a respect for the facts."
But it is not just the volume of herbicides used that raises concerns. One of the main herbicides ForestEthics claimed is heavily used by Sierra Pacific is atrazine, which has been found to disrupt reproductive functioning and cause liver, kidney and heart damage in animals -- and possibly, some research suggests, in humans.
The ForestEthics analysis found that Sierra Pacific applied 91,450 pounds of atrazine to its tree farms in Northern California between 1995 and 2007.
"This is important information that needs to get out to the public," said Tyrone Hayes, an endocrinologist at the University of California, Berkeley, who has studied atrazine and reviewed the ForestEthics analysis.
Trying to fill a void
A challenge to assessing the issue is the lack of national data. No national agency is keeping close tabs on the use of herbicides by the timber industry, researchers and government officials say. As a result, "There's very little data on forestry use of herbicides," noted William Battaglin, a hydrologist at the U.S. Geological Survey office in Denver.
California, which maintains the pesticide database that ForestEthics used for its analysis, is the only state that requires commercial users to submit detailed pesticide reports.
U.S. EPA is responsible for regulating the production and use of pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act. But when asked by Land Letter to provide data on the use of pesticides nationwide, the most recent statistics EPA could provide are not very detailed and date back to 2001.
That year, more than 1.2 billion pounds of pesticides were used nationwide, the majority of which were herbicides used to control vegetation. More than 75 percent of the pesticides in the country are used by the agricultural sector, and atrazine was the second most commonly used herbicide, according to the EPA data. But EPA's information does not include a breakdown of how much each specific industry uses.
USGS has done some groundbreaking studies on the agricultural use of herbicides nationwide but not of the timber industry, Battaglin said. He thinks someone should, noting that he and his colleagues conducting research in Colorado are sometimes amazed to capture water samples containing high levels of herbicides in locations where there is little or no agricultural activity.
"We can't eliminate that the herbicides [in the water] were used in forestry," Battaglin said.
It is this uncertainty that sparked ForestEthics to spend six months analyzing the state database, said Buswell, the ForestEthics campaigner.
The timber industry has said for years that it only applies herbicides to a plot of land in which the trees have been clear-cut and harvested. This is done to prevent weeds, grass and shrubs from smothering young seedlings and is done only a few times on each acre over the course of a century, industry officials maintain.
But the ForestEthics analysis of the state database found areas sprayed with herbicide as many as 10 times between 1995 and 2007. "That's not always the case," Buswell said, "but you can't support the claim about areas being sprayed once every 80 years."
Human health impacts
Though concerns have been raised over a range of pesticides, the chief concern is the use of atrazine, a weed-killing herbicide commonly applied to everything from evergreen tree farms to sugarcane and corn crops, according to the federal Agency for Toxic Substances and Disease Registry.
Hayes, the Berkeley endocrinologist who has studied atrazine, points to studies that have found reproductive problems in men exposed to atrazine as well as higher incidence of breast cancer in women living in areas where atrazine was found in the drinking water supply.
"There is no independent scientist who would tell you that it doesn't do anything," Hayes said.
But EPA is not convinced that atrazine is a significant health threat. In 2006, EPA issued a report on human health risks associated with a group of herbicides that includes atrazine and concluded that the cumulative risks of each are below the agency's overall "regulatory level of concern."
Still, Sue Lynn of Montgomery Creek, a small town just outside of Sierra Pacific's headquarters in Redding, Calif., is worried. Atrazine is the second most detected pesticide in drinking water wells nationwide, according to a national EPA survey cited by ForestEthics.
"The astounding quantities of herbicide being sprayed in our forests outrages me," Lynn said. "They do not have the right to poison the land and the watersheds that provide drinking water for Californians."
Studies have found that atrazine can cause male frogs to grow ovaries. It is also suspected to have caused male fish in the Potomac River to grow eggs.
The ForestEthics study also raises concern about imazapyr, finding that Sierra Pacific sprayed more than 31,000 pounds of imazapyr on its California properties. Imazapyr has been shown to increase the number of brain and thyroid cancers in male rats and can be persistent in soil for up to a year.
There is legitimate concern about the effects of these herbicides on amphibians and other wildlife, said Don Erman, an aquatic ecologist and professor emeritus at the University of California, Davis. Erman points to studies that show that "this sort of chronic level exposure to low concentrations of some kinds of herbicides has adverse effects on wildlife, particularly frogs."
The concern is not limited to wildlife. "I think whenever you see chemicals that affect the reproductive conditions in any other animal, it should raise eyebrows about how it affects humans," Erman said.
Sierra Pacific Industries officials insist there is absolutely nothing to worry about, and that ForestEthics has blown the company's use of herbicides way out of proportion.
For one thing, the application of herbicides is "strictly controlled" by the state, said Mark Pawlicki, Sierra Pacific's director of government affairs.
"We are required to use chemicals approved by both the state and the EPA," Pawlicki said. "We must apply them based on standards set by each county, and they can only be applied by a person who is a licensed applicator."
By comparison, two-thirds of the herbicides in California are applied by homeowners, who are not required to adhere to strict application standards and are not mandated to report to the state, he said. Nationwide, EPA has estimated, 41 million households use herbicides in their yards every year.
Pawlicki said the company makes an effort not to apply the herbicides near lakes, rivers or streams. Even so, the company has taken "tens of thousands" of samples from nearby waterways that it submits to EPA for analysis.
"We have never had a detection of a chemical in the water," he said. "The argument that these chemicals are getting into the water is just not true. They have made a mountain out of a molehill."
Pawlicki and others said the ForestEthics study unfairly singles out the timber industry, and Sierra Pacific specifically, for scrutiny. Industry officials say the timber industry uses far less pesticides than other private land-use industries, particularly agriculture.
"Despite what some activists would lead the public to believe, the forestry industry is actually one of the smallest agricultural users of chemicals," said Milburn, the American Forest & Paper Association spokesman.
While Sierra Pacific used more than 770,000 pounds of pesticides on its tree farms in Northern California between 1995 and 2007, farmers in the state's largest agricultural county, Fresno County, used an estimated 350 million pounds of herbicides during the same time period, Pawlicki said.
"That's why this thing is so distorted," he said. "It makes it look like we're the biggest user of these chemicals, and that's just not true."
Buswell said ForestEthics is willing to concede that the herbicide use among the timber industry is less than other industries. "But given these herbicides are being applied at the headwaters of drinking water supplies and in areas of abundant wildlife habitat, it's not too much to ask them to look at minimizing herbicide usage," he said.
The need for change
While insisting that its herbicide spraying practices are safe, the timber industry has taken steps on its own to use different chemicals. Sierra Pacific has significantly reduced its use of atrazine, applying it only when necessary, Pawlicki said.
"We have almost stopped using atrazine completely," he said.
Pawlicki said it is not realistic to just stop using herbicides. If the company did, he said, it would lose acres of tree farms to weeds and shrubs. "It's a very important tool at our disposal," he said of the herbicides.
But Erman, the aquatic ecologist, said there are other ways to ensure that tree seedlings are not snuffed out by weeds and tall grass. One way is to not clear-cut all the mature trees at once, but rather to grow and harvest sections of trees so that there is a canopy of shade that does not spark the growth of weeds and grass.
"I'd like to see less reliance on pesticides," Erman said.
Hayes agrees that better land-use practices will reduce the need for so many chemicals to control vegetation. But he also says some herbicides simply need to go.
"What needs to happen is chemicals that are biologically disruptive have to be taken off the market," Hayes said.
That includes atrazine, which is manufactured by a company in Switzerland, where the use of atrazine is banned. An estimated 80 million pounds of atrazine is used in the United States each year, Hayes said.
"Clearly, we need to consider health effects on wildlife," he said.
Scott Streater is a freelance journalist based in Colorado Springs, Colo.