Integrative Invasive Species Management
Siuslaw National Forest | Summer 2024
The Siuslaw National Forest is proposing a Forest-wide project to reduce the presence of invasive plant species populations and restore native plant ecosystems.
Please scroll down to learn more about the project. Be patient for web maps to load. If you’re having problems viewing this website and you are using Internet Explorer, please try Google Chrome, Mozilla Firefox, Microsoft Edge or Apple Safari. This content is best viewed on a desktop or laptop computer.
Photo Above: An open area near Rock Creek Wilderness showing fox glove, an invasive species. All photos were taken by USDA Forest Service Employees and or selected from Forest Service archives.
Project Location
The Siuslaw National Forest stretches 630,000 acres from the western slopes of the coast range mountains to the Oregon Coast.
The Siuslaw currently has approximately 57,000 acres infested with non-native and invasive terrestrial plant species. The infested areas are likely underestimated due to incomplete inventories and the ongoing spread of invasive plants.
Click on the button in the lower left corner of the interactive map to view the legend. Use the map navigation tools to zoom and explore the extent of mapped plant populations.
Background Information
Invasive European beachgrass in the Oregon Dunes National Recreation Area on the Siuslaw National Forest.
What is an invasive species?
An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.
Photo Left: An area overtaken with old man’s beard, an invasive climbing weed.
Conditions are expected to worsen as climate change modifies the distribution and dispersal of nonnative plant species providing opportunities for establishment by nonnatives, particularly in areas impacted by fire.
Currently the Siuslaw National Forest has no comprehensive strategy for prioritizing and treating invasive botanical species across the landscape.
This results in treatments designed on a project-by-project basis, leading to inconsistencies and limiting the Forest’s ability to treat newly discovered populations in a timely manner or to take advantage of partnership opportunities.
Photo Left: A youth crew manually removing scotch broom on the Oregon Dunes National Recreation Area.
Without additional action, invasive plant populations will continue to grow on National Forests System lands, which would compromise our ability to manage for healthy native ecosystems, reduce resiliency in the face of climate change and contribute to the spread of invasive plants to neighboring lands.
Common Invasive Species
See five of most common invasive species on the Siuslaw National Forest highlighted below. Use the map navigation tools to zoom and explore the extent of mapped plant populations.
Scotch Broom
Scotch broom is a shrub that is a member of the pea family native to Europe and North Africa. It was planted to stabilize and provide nutrients to the moving sand in the Oregon Dunes National Recreation Area. Now it is the most common invasive species on the Siuslaw National Forest.
European Beachgrass
European beachgrass is a coarse grass native to Europe and North Africa. It stabilizes loose sand by efficiently forming networks of rhizomes and roots. It can grow up to six and a half feet laterally in six months, rapidly changing the structure and ecology of dune ecosystems.
Common Gorse
Common gorse is a prickly shrub in the pea family native to Europe. It forms dense stands that crowd out other vegetation and has seeds that can survive over 30 years in the seed bank.
Himalayan Blackberry
Himalayan blackberry is a tenacious member of the rose family native to Eurasia. It forms dense thickets and prevent native species from growing and wildlife from moving through an area.
Bull Thistle
Bull thistle is a member of the aster family native to Europe, West Asia, and Northwest Africa. Its large rosettes can commonly be found in disturbed areas.
Proposed Action
The project proposes to restore ecosystems by reducing the presence of invasive plant species populations across the entirety of the Siuslaw National Forest (630,000 acres). To meet the established needs of the project, treatment methods considered would include chemical, manual, mechanical, and biological. Different tools would be used in different areas based on site specific situations and/or land allocations. As some of the herbicides included with the proposed action are not covered under the Regionwide Environmental Impact Statement , a Forest plan amendment is necessary.
Photo Right: Volunteers pulling invasive species near Heceta Beach, OR.
Description of Treatments
Tansy ragwort in seed near Alsea, OR.
An Integrated Pest Management (IPM) control approach employs a combination of treatment methods. Successful treatments often last years, sometimes requiring multiple treatments per year, involving a combination of methods. The treatments are tailored depending on:
- Specific invasive plants species and unique biology (e.g. mode of reproduction)
- Population size and density
- Site type (e.g. disturbed roadside, riparian, upland)
- Prior treatments and their effectiveness
To read more details about the types of proposed treatments click here .
Manual Methods
Forest Service employees pulling Scotch broom seedlings by hand.
- Pulling by hand or using tools
- Clipping
- Cutting
- Mulching
Use the swipe tool below to view the before and after results of manual removal of scotch broom.
Before and after the removal of scotch broom by hand and using tools.
Biological Methods
- Insects – Insect species that are natural enemies of specifically targeted species of invasive plant are introduced. These species are carefully screened by the US Animal and Plant Health Inspection Service (APHIS) to prevent damage to unintended hosts.
- Livestock – Livestock, usually goats, are penned into a limited area infested with invasive species such that they have little choice but to graze on the target plant. They are left to graze for a short period of time until the target plants are consumed. Impacts to water and soils would be considered when designing this prescription.
- Soil solarization and shading
Tarps shading unwanted vegetation near Sand Lake Recreational Area.
Mechanical Methods
Weed removal using a steamer.
- Mowing or cutting with a hand-held string or blade trimmer
- Propane torch
- Prescribed burning
- Scraping
- Power raking
- Steaming
Firefighters conduct a prescribed burn to remove invasive European Beach grass at Tahkenitch Beach.
Chemical Methods
Blue dye is mixed with herbicide to trace what areas have been sprayed when using backpack sprayers to direct foliar spray.
- Hack and squirt or frill
- Cut and daub
- Injection
- Basal Bark
- Wiping onto foliage
- Directed foliar spray
- Spot spray
- Drone application
Left: A plastic pipe with a flow regulator and sponge on the end is used to apply herbicide when cut and daubing. Center: Cut stumps being daubed with herbicide just after cutting. Right: Cut stumps a few days after cut and daub herbicide treatment. This treatment prevents the roots from suckering.
Site Selection & Treatment Prescriptions
Treatment areas will be identified based on established priorities. This includes invasive species that are both widespread and limited, have a high probability of spreading and that occur in sensitive areas, such as Scenic Botanical Areas.
Once identified, a prescription for treatment will be developed considering the biology of the invasive species, size of the population, success of past treatments, feasibility of treatment options, consistency with Forest Plan standards and guidelines, and sensitivity of the area. Post treatment, areas will be monitored for degree of success of the treatment.
Project Timeline
Tansy ragwort in an area that was recently harvested.
June 2024
Initial Feedback.
Fall 2024
Draft Environmental Assessment release and Public Comment period.
Winter 2025
Final Environmental Assessment released.
Spring 2025
Anticipated decision.
How to Comment & Stay Engaged
The project page can be found at https://www.fs.usda.gov/project/?project=66006 . We will have opportunities to provide feedback over the course of the project, with one starting in late June. Visit the project webpage for more details.
The Get Connected section of the project page provides direction on how to:
Request More Info Comment or Object on Project Subscribe to Email Updates
For information about the Forest-Wide Invasive Species Project on the Siuslaw National Forest, please contact Chelsea Monks, Forest Botanist, at chelsea.monks@usda.gov
Fox glove growing on the Siuslaw National Forest.
How can I help?
There are several ways to prevent movement of invasive species. Plant species generally regenerate using seeds or sections of the roots and stems. To help stop invasive species spread, remove plants, seeds, and mud from your boots, gear, pets, and vehicle. You can do this by cleaning them before recreating and again before leaving the area.
Another way to prevent the spread of invasive species is to consider planting native species in your yard. Native species are already adapted to the local environment and may require less water than their ornamental counterparts.
For more information, check out PlayCleanGo.org and the Oregon Department of Agriculture’s Weeds and WeedMapper page.
