14 minute read
Herbicides in Oregon Forests
Spray Notice
Herbicides are quietly simplifying and tainting Western Oregon’s timberlands
written and photographed by Daniel O’Neil
Western Oregon is a fertile land. The conifer forests that expand west from the Cascade Crest to the coast grow on some of the world’s most productive forestland. Plenty of rain, rich soil and enough sun nourish all sorts of plant life here. The area is the country’s top producer of softwood lumber and plywood, necessary goods that Oregon can naturally provide.
With only conifers in mind, primarily Douglas fir, foresters here have long considered competition from other plants a hindrance to reforestation. Water, sunlight and soil nutrients are precious commodities for a merchantable crop like trees, so landowners prioritizing timber production insist these elements feed conifer seedlings and nothing more in the first several years after replanting. Herbicides help them do that.
Herbicides, however, don’t just make way for the re-emerging forest. Their lethal power undermines the foundation of a healthy forest by eradicating other important plants like hardwoods and broadleaf shrubs. This, in turn, affects the animals, birds and insects that rely on such understory plants for habitat and food. Herbicides, many of which can pose severe health problems for humans and for endangered species like salmon, also make their way into the streams and rivers that drain the forests.
Ever since their introduction into Oregon’s woods in the 1960s, herbicides have served as a linchpin in forestry here. Herbicides have also fueled passions and debate over their harm to humans and the forest ecosystem. Whether or not Oregon needs herbicides to produce profitable timber depends on how you look at it. For those in favor of a healthy, resilient, functioning forest, the widescale use of herbicides deserves questioning.
In forestry, herbicides serve two purposes. One involves the control of invasive plants like Scotch broom and Himalayan blackberry that can quickly replace native plant species. Even herbicide skeptics accept this targeted use. The other, far more widely used purpose is to eliminate any vegetation that, post-clearcut, might compete with replanted conifer seedlings. Here begins the polemic of herbicide use in Oregon’s forests.
Some of the most popular herbicides used on Oregon’s forests include familiar names and usual suspects. Glyphosate, the active ingredient in Roundup, is considered a “probable” carcinogen by the International Agency for Research on Cancer. Another standard forestry herbicide, atrazine, is banned in the European Union. The herbicide 2,4-D is listed as a “possible” carcinogen by the IARC, and was one of two key components in Agent Orange—the other component, 2,4,5-T, triggered enough controversy in Oregon’s woods in the 1970s that it isn’t used here anymore.
Because the state’s arid east side doesn’t grow a raucous understory of plants, herbicide use affects forests in Western Oregon. The total amount used each year remains unknown because spray application records are not routinely reported to any governmental agency. But a study by Oregon State University researchers found that chemical applications cover “potentially 1 million acres of Oregon forest land annually, with the vast majority of these herbicides being applied to harvested units.”
How herbicides are applied, or not applied at all, matters. Controlling competitive vegetation is only necessary after replanting a clearcut, a disturbance that opens the land up to the plants, including invasives, that emerge to re-establish the natural order. Spraying herbicides is the norm across most of Western Oregon’s industrial and state-owned timberlands, which account for nearly three-quarters of the timber harvest here, and where clearcutting remains king. A dose—or two, or three, or maybe four—of herbicides arrests competition in the first few years of post-clearcut regeneration.
Ground-based applications, often with backpack sprayers, offer a somewhat precise method for applying herbicides. But on rugged terrain, all too common in Western Oregon, aerial spraying takes over. Like a crop duster, a plane or helicopter covers the clearcut, leaving wind drift as a serious, contentious issue because the toxic spray can travel far from its intended target, into waterways and onto communities. In 2017, Lincoln County voted to ban aerial herbicide spraying, the first county in the nation to do so. But a judge overturned the ban because Oregon state law preempts county rules on pesticide use.
Competitive vegetation and invasives can be controlled without herbicides—mechanically, with chainsaws and bulldozers—but this requires extra time, labor and expense. The Forest Service and the Bureau of Land Management prove it’s possible, but they don’t manage their lands exclusively for timber, and they don’t clearcut in Western Oregon anymore. Heavy logging and spraying led to a federal court injunction in 1984 that prohibits those agencies from using herbicides, with exceptions for invasives.
Jim Furnish, who served as the Siuslaw National Forest supervisor in the 1990s and later as deputy chief of the Forest Service, admitted that herbicide-free forestry wasn’t easy. “It was more costly, more labor intensive,” he once told a reporter. “But forestry in Oregon is profitable under many different scenarios. The Forest Service just saddled itself to a different horse and rode off into the future.”
When droplets of herbicide hit the earth, certain, or all, plants soon die. With them goes biodiversity, the backbone of a healthy forest. Like a symphony, biodiversity relies on a wide range of contributors. The variety of early-successional plants that sprout after a disturbance, like wildfire or a clearcut, work hard to renew life below and above ground, offering habitat to the many species of fauna that make a forest ecosystem complete.
“If you look at the developmental sequence from a disturbance, the early-successional ecosystem is the most biodiverse stage in the entire developmental period of the forest,” said Dr. Jerry Franklin, a forest ecologist and University of Washington emeritus professor world-renowned for bringing a new, holistic view to forest management in the Pacific Northwest.
Herbicides inhibit the early-successional forest, and Franklin often cannot believe his eyes. “If it’s green, and it’s not a Douglas fir, kill it,” he said, mocking the dominant view of intensive forestry. “When you see some of the harvest units in Western Oregon, it’s stunning. They’re brown. There’s nothing green out there. They’ve cleaned it all off and then sprayed it, and there isn’t anything out there until they get some trees growing again. It’s brown-earth forestry.” The consequences of repeated herbicide treatments strike deep. After multiple harvest cycles and the accompanying herbicide sprays, crucial plant species can disappear altogether, along with their seed banks underground and any species-dependent fauna. On steeper, denuded terrain, barren topsoil can slide downslope, complicating forest regeneration.
“To treat such an ecosystem as a farm blows my mind,” said Dr. Deke Gundersen, who taught environmental toxicology at Pacific University for twenty-three years, where he is now professor emeritus. “Let’s cut everything down, replant with the same species, and spray it with herbicides to make sure nothing else grows. I guess we don’t want forests anymore, is what we’re saying, because to me a forest is a multi-layered, complex, diverse system that provides a variety of benefits for the organisms that inhabit that system and for the people living near that system.”
A forest simplified by herbicides cannot work in all of its mysterious, wondrous ways—from cleaning our water and capturing carbon to providing habitat for elk, salmon and other foods. Simplified forests also lie more vulnerable to the effects of climate change, including losing their resilience to, and ability to recover from, wildfire.
Dr. Matthew Betts, an Oregon State University professor and Ruth Spaniol Chair in the Department of Forest Ecosystems and Society, has studied forest biodiversity closely. In 2009, he and colleagues undertook an experiment in Oregon’s Coast Range to evaluate the effects of different herbicide regimes: from none at all, to a light, moderate and intensive treatment. They then spent years measuring biodiversity in the form of birds, mammals, insects, replanted conifers and more.
“We found, of course, that herbicides reduce plant richness—that’s what they’re designed to do,” Betts said. “And that does have a bottom-up effect on biodiversity. If you reduce plant richness, you tend to get fewer arthropods, you tend to get reduced numbers of bees, and for some species of birds, the effect was quite negative, especially in the first three or four years of the study, the negative effects jumped out.”
While Betts and colleagues found that herbicide treatments increased yield significantly, up to 30 percent under the intensive application, they also observed relatively little overall difference in biodiversity between the “light” treatment—one herbicide spray before replanting—and the nonherbicide control areas.
The Oregon Department of Forestry employs a version of this “light” application on state forestlands. Where seedlings are struggling, a second treatment is applied—last year, about one-third was resprayed. According to John Walter, ODF State Forest Division silviculturist, longer harvest rotations—growing trees for fifty to eighty years—allow for less herbicide.
“It depends on your goals,” Walter said. “With state forest, if the goal is an 80-year-old stand at final, we don’t need to get those trees rocketing out of the ground by controlling all the vegetation,” Walter said. “If it’s a little bit slower, that’s fine because they will still get to be big, mature trees at 80.”
Industrial forestry follows what Betts labeled a “moderate” spray program. Short rotations, between thirty and fifty years, followed by multiple sprays over the course of several years is the typical industrial regime, even though the Douglas fir’s growth spurt begins around age 40 and ends at about age 100.
Nearly all of today’s industrial timberland owners are some form of investment organization. Return on capital dictates their forest management plans, and market economics require forests be harvested young. Herbicides help speed things up.
“We don’t apologize from a private-land standpoint,” said Seth Barnes, director of forest policy for the Oregon Forest Industries Council (OFIC), a trade association representing industrial timberland owners. “We’re growing trees to meet the world’s lumber demand.”
Barnes recognizes that by eliminating competitive plants in the early phase of a replanted forest, herbicides prove their value in added tree growth. “Herbicides are an important tool for us to use, and really the only tool in some instances to ensure that the forest is re-established in a timely manner.”
In a way, Oregon law encourages the use of herbicides after a clearcut harvest on state and private timberlands. The “free-to-grow” requirement in the state’s Forest Practices Act states that replanted conifers must be taller than competing vegetation by their sixth year.
Those opposed to the widespread use of herbicides argue that “free-to-grow” made sense before reforestation was required, but no longer today—modern tree nurseries and replanting techniques have evolved so much that controlling competition with herbicides is unnecessary.
Industrial forestland owners have no complaints about “free-to-grow” because it’s already in their best financial interest to replant quickly and efficiently. In fact, herbicides help them attain another state-mandated threshold, the “green-up” rule. Before a stand can be clearcut, that landowner’s trees in adjacent parcels must be “free-to-grow.” The sooner a clearcut is “free-to-grow,” the sooner the neighboring stand can be cut and sold.
Today’s short-rotation forestry looks short-sighted to Franklin. “The only people who benefit from it are people who essentially own the forest in order to get a return on investment,” he said. “Most small private, non-industrial landowners don’t do that. They don’t own the land in order to maximize the capital return from that land. They have other values.”
Public and private forestlands provide more than three-quarters of Oregon’s municipal water supplies. Yet data on herbicide toxicity goes lacking. For one thing, experiments on humans are not an option. Funding is limited. And testing is problematic because the chemical companies are responsible for testing their own products, and they only analyze the active ingredient, not the actual product.
“It’s like the fox watching the henhouse,” Gundersen said. “We really don’t know a hundred percent how safe they are. Particularly here in the Pacific Northwest, very little, if any, studies look at the direct impacts of these herbicides and related chemicals on human health, especially when it’s related to drinking water.”
Beyond the direct effects of chemicals, indirect effects from clearcuts and herbicides can also imperil drinking water. Sediment caused by logging roads and by brown, herbicide-treated slopes enters drinking watersheds, especially along the Oregon Coast. When the organic matter in the sediment reacts with chlorine used for disinfecting tap water, chemical byproducts such as trihalomethanes form, and these can cause cancer and reproductive problems.
Rockaway Beach sources its drinking water from Jetty Creek, a series of steep drainages just northeast of town. The watershed was intact in the late 1990s, but since the early 2000s, industrial timber companies have removed nearly 90 percent of that forest. Residents began receiving water quality alerts for toxins like trihalomethanes in 2005. Eventually a new $2 million water treatment plant was required to filter out the sediment. The city is now raising funds to buy the watershed.
Rockaway Beach resident Nancy Webster co-founded North Coast Communities for Watershed Protection in 2012, demanding that timberland owners stop logging and spraying in watersheds. Similar groups have since organized up and down the Oregon Coast.
“The industry is deciding what the best protections are for our watersheds,” Webster said. In response, Webster, whose father worked in Oregon’s timber industry, and other volunteers raise community awareness through actions like circulating petitions against aerial herbicide spraying. “People from the timber industry come up and sign the petition, and it’s shocking. They tell us their stories. Some people have been exposed, or some people don’t like the clearcutting and fear for their drinking water.”
A 2018 survey of Oregon Coast voters, commissioned by OFIC, found similar results—a majority approved of logging, but disapproved of aerial spraying. “Voters who have immediate family employed in the timber industry or are employed themselves oppose aerial pesticides at the same rate as voters overall,” the report said.
Oregonians can use their voices, wallets, votes and citizens’ initiatives to shape the present and future of forests here. New objectives, like encouraging hardwoods that provide benefits such as wildfire resilience and increased water supply, could be pursued. Prohibiting pesticide spraying, and requiring eighty-year rotations, in drinking watersheds would boost biodiversity while protecting Oregon communities. Incentives not to use herbicides, and community-owned forests, present other options. All of this can coexist with the necessary, respectable task of cutting trees for wood.
Removing the “free-to-grow” requirement would allow small private forestland owners to pass on herbicides, or they could instead harvest trees from their land without relying on clearcutting and herbicides. The easiest way to limit those chemicals is to stop clearcutting, like the federal agencies did forty years ago.
“If our goal is to produce wood, we would extend harvest rotations and then get more wood per acre that way instead of having these super-short harvest rotations with herbicide,” Betts said, with a caveat. “The potential consequence is that we need to expand our forestry footprint. If we’re not regenerating forests fast enough, it means we need to go somewhere else to get timber. The best thing we can do is to reduce wood consumption, but that doesn’t seem to be happening at the moment.”
As this century advances, bringing with it greater threats from a changing climate, a re-think of how Oregon uses its forests, a revaluation, is in order. “We need to step back and take a look at our forests, to see what we’re really getting from them as a whole, and not look at them as just a source of lumber,” Gundersen said. “I think there’s a lot more that human beings can gain from our forests than just wood products.”
