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U.S. DEPARTMENT OF THE INTERIOR

BUREAU OF LAND MANAGEMENT

Oregon / Washington

Noxious Weeds, Invasive Plants, and Harmful Vegetation...Oh My!

What's up with all the weeds infesting millions of acres in Oregon?

story by Maya Fuller
photos by John Craig


Like something that's stepped of the science fiction classic, The Day of the Triffids, Oregon's rampant vegetation is seemingly taking over landscapes, driving away native wildlife, and making everyone from ranchers to botanists to fishermen just a little nervous.

What can be done about this invasive foliage before its populations grow to overwhelming numbers?

Weeds infest an estimated 6.4 million acres across public lands in Oregon and Washington. And this figure has been increasing at 10 to 15 percent per year. These plants are considered invasive because they are not native to Oregon and because they spread rapidly.

In eastern Oregon, plants with creative names like yellow starthistle, perennial pepperweed, and medusa head are known to poison livestock, increase the frequency and intensity of wildfire, and displace native vegetation.

Other vegetation like Himalayan blackberry, scotch broom, and japanese knotweed are examples of plants that threaten the west side of the state - dominating riparian habitats, degrading water quality, and competing with trees and forage plants that are important to fish, wildlife and endangered species.

To address this issue, the Bureau of Land Management is undergoing a planning effort to analyze the effects of herbicide use on Oregon's BLM lands as one of its many tools to control noxious weeds, invasive plants, and other weeds. The plan, titled Vegetation Treatments Using Herbicides on BLM Lands in Oregon Environmental Impact Statement (EIS), will focus on the effects of updating the list of herbicides available for use in Oregon. However, the EIS will not evaluate the use of herbicides for commercial timber enhancement or livestock production.

Noxious Weeds, Invasive Plants, and Harmful Vegetation...Oh My!
photo by John Craig

The challenge with many of these menacing invaders is that there is no perfect methodology for eradication. The BLM already uses techniques like burning, digging, mowing, and pulling whenever possible. Unfortunately, with some species these are not effective strategies. With more problematic varieties, often the only effective technique is to use herbicides.

Currently, Oregon BLM uses only four of the 18 herbicides that have been approved for use on BLM lands nationally. The Oregon Vegetation Treatments EIS is being prepared in part to respond to a 1984/87 U.S. District Court injunction, and also because 14 of the herbicides would be new to BLM lands in Oregon.

The BLM's overall objective is to see if a broader array of herbicides that are more target-specific and more effective at controlling noxious weeds, invasive plants, and other weeds could be safer and more effective than the current system. Used in combination with other management practices, additional herbicide treatments may slow the spread of noxious weeds and invasive plants, which in turn helps restore ecosystem health and watershed functions.

The BLM manages over 15 million acres of public lands in Oregon and currently treats approximately 22,000 acres of designated noxious weeds each year. Of those 22,000 acres, approximately 12,000 acres are treated with herbicides and the remaining 10,000 acres are treated mechanically, manually, with biocontrols, and with other non-herbicide methods. The BLM scoping period to study the impact of additional herbicides ended July 28, 2008. Work has begun on the Draft EIS which will be available in May 2009.

It's not just their names that are frightening. These species can disrupt entire ecosystems. Some have the power to destroy entire forests while others can convert grasslands into deserts with no value to animals or humans. Given this level of threat, inaction is not an option.

The BLM, steward of our nation's public lands, will continue to test and explore additional methods to protect and improve this landscape for the use and enjoyment of all Oregonians for years to come.


Visit us online to learn more about the BLM's invasive weed management program.