By George Wuerthner

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I recently attended a presentation on invasive weeds by a representative of the Deschutes National Forest.

The problem with the presentation was that it promoted and legitimized an industrial paradigm to weed threats. The U.S. Forest Service promotes an industrial forestry paradigm that treats the symptoms, not the causes of ecological degradation.

The biggest factors contributing to the spread of weeds on public lands comes from logging/thinning and livestock grazing. Yet during the entire Forest Service presentation, the one thing missing from the talk was any mention of why and how weeds are spread. Most species that we consider weeds are plants that thrive on disturbance. In other words, activities that create bare soil and/or reduce the viability of the native species to compete against weed species thus promote weed invasions.

While many factors can promote weed spread, including even hiker’s boots, the biggest factor on public lands is the result of the large-scale disturbance that comes from logging and livestock grazing.

Talking about invasive plants without addressing the ultimate factors that facilitate weed establishment is like listening to a medical team discuss lung cancer and how to treat it with radiation, chemo and drugs — and never once even alluding to the fact that most lung cancer is frequently the result of smoking cigarettes.

The Forest Service weed coordinator focused her talk on specific species that are considered problematic and the means of controlling them using herbicides and promoting things like “weed pulls” but never discussed how private commercial activities on public lands like logging and grazing are typically the major vectors for weed spread.

For instance, logging/thinning by creating extensive areas of bare soil and disturbed ground and the purposeful destruction of native shrubs creates the perfect habitat for weed invasion. (Just drive the Cascades Lakes Highway and view the “thinning” operations for exhibit A, B and C).

Plus, logging roads become linear corridors for weed spread and “inoculate” new sites with weeds. Even though the Forest Service requires logging equipment to be washed before entering a logging location to preclude weed-seed spread, such tactics are not 100 percent effective. Plus, this does not prevent soil disturbance and the destruction of native plants caused by logging operations.

And once logging roads are created, they become travel corridors often open to the public whose vehicles are not washed, not to mention mountain bikers and off-road vehicles that commandeer these pathways, helping to spread the seeds of weeds as well.

Livestock grazing has a similar impact on rangelands. By crushing and destroying biocrusts that cover soils, livestock creates the perfect seedbed for weed establishment. Livestock through excretion of manure can carry weed seeds into many remote areas and can “fertilize” sites aiding even more weed spread.

Furthermore, because cattle consume the preferred native grasses, weakening their ability to compete against weeds, the continued presence of livestock gradually leads to more weed invasion.

When I confronted the Forest Service representative and asked why she did not even mention logging/thinning and livestock grazing, she responded: “Well, you are never going to eliminate logging or grazing.”

And I guess she will always have a job too because as long the agency fails to confront the factors contributing to weed spread, we will be involved in an endless and losing battle against invasive weeds.

Besides spending money trying to control weeds on our public lands (and providing long-term job security to weed coordinators who fail to provide the full picture to the public), we are losing the biodiversity, the watershed protection and wildlife habitat that intact ecosystems provide. These costs are never internalized because the Forest Service promotes commercial economic activities at the expense of ecological sustainability.

— George Wuerthner is a former botanist for the Bureau of Land Management and worked extensively on weed ecology. He lives in Bend.

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