Welcome! This site is intended to disseminate highlights of research findings from a Joint Fire Science Program (JFSP) sponsored project that focused on assessing responses of southwestern Oregon's chaparral and oak woodland plant communities to fuel reduction thinning treatments. These plant communities, which are among the least understood in the Pacific Northwest, were also characterized and mapped as a part of this project. Findings summarized here advance both basic understanding of these ecosystems, and provide valuable information to the land managers that oversee them.
Personnel from the Medford, OR office of the Bureau of Land Management (BLM), Oregon State University (OSU), and Southern Oregon University (SOU) gathered and analyzed data largely from oak woodlands, shrublands, and chaparral in the Applegate Valley to answer the following questions:
These research components are described briefly below. Follow the links in each section for elaboration, or try the Publications link for the complete works. Background information on the Applegate Valley and more on why these projects are important follows (or try the Tools for SW Oregon link for maps, plant species lists, GIS layers available, and more!).
- What plant communities comprise the nonconiferous component of vegetation in the area, and how does their occurrence relate to site conditions and disturbance history?
- What are the consequences of fuel reduction treatments for native plant communities or native plant species of concern?
- What is the relationship of fuel reduction treatment to invasion by exotic plants?
- Is seeding of prescribed-burned sites with native grasses effective at encouraging their establishment or inhibiting invasion by exotic species?
- Do wildfires behave differently in areas that have been thinned compared to unthinned but otherwise similar areas?
This study assessed the relationships of environmental and disturbance variables to current vegetation composition in grassland, shrubland, and woodland vegetation types. Field surveys were used to define and map 13 plant assemblages. GIS was used to investigate patterns of assemblage occurrence on the landscape in relation to site conditions and disturbance history. This benchmark assessment provides detailed vegetation maps and baseline data important for monitoring change over time, and aids in understanding and conservation of unique vegetation types. Go to report.
Right: GIS image near Ruch, OR, of non-coniferous vegetation associations characterized and mapped on BLM lands by Eric Pfaff.
How do fuel reduction treatments affect understory plant communities and site conditions? Do treatments favor native species or foster expansion or invasion of exotics? Do different plant trait groups respond differently to treatment? Do effects differ between treatment types (hand-cut and pile-burn versus mechanical mastication)? To answer these questions, vegetation and abiotic characteristics were measured along paired transects in thinned and unthinned chaparral and oak-shrub communities. The central goal of this study was to provide information on responses of these communities to fuel reduction treatments to assist land managers who want to design treatments that achieve fuel-reduction or restoration goals without exacerbating problems with invasive species. Go to report.
Right: Aerial photgraph of vegetation after fuels reduction in the Applegate Adaptive Management Area. Photo courtesy of the BLM.
The Buncom Bowl fuel-reduction project in the Applegate Valley of Southwest Oregon was burned by the Squires fire (2002) before project completion. Prior plant community mapping, permanent transects, and established photo-points together with post-fire surveys provided an opportunity to view fire interaction with treated and untreated woodland and chaparral stands. Post-fire site and vegetative conditions were compared among handcut-piled-and-burned (HPB), handcut-and-piled only (HP), mechanically masticated (SB), and untreated sites. How is post-fire vegetation survival and structure different between treatments? How does wildfire interact with fuel manipulations to affect soil and seedbanks and determine future vegetation? Go to report.
Right: Oaks burned by the Squires Fire. Photo by Paul Hosten.
The Interior Foothills of the Klamath Mountains Ecoregion (PDF) of southwestern Oregon and northern California are located at the junction of the Cascade, Sierra, and Coastal mountain ranges. The joining of these major mountain axes and the wide range of soil types that occur in the Ecoregion has resulted in unusually diverse plant life. The area supports some of the least understood ecosystems in the Pacific Northwest. Our studies focused on oak woodland, shrub land, and chaparral habitats in the Applegate Valley, one of southwestern Oregon’s interior valleys (click for map).
Fire is the key natural disturbance in southwestern Oregon, and has been influential in shaping the landscape. Many local plant species, and the animals that depend on them, rely on fire to maintain their habitats. However, nearly a century of fire suppression is thought to have resulted in unnaturally large accumulations of fuel, which may exacerbate fire risks. Fire suppression is also thought to have caused changes in many plant communities, including the low elevation oak woodlands, shrub lands, and chaparral studied here.
In response to concerns about fire risks in the region, particularly in wildland/urban interface areas, land managers are carrying out fuels reduction programs intended to reduce fire hazards. In some cases, it is hoped that treatments will also restore ecosystems that are assumed to have been altered by fire suppression. The Medford, OR District of the Bureau of Land Management (BLM) manages lands that are interspersed in a checkerboard pattern with private holdings (map). The agency has been carrying out a fuel reduction thinning program on its lands since the mid 1990s. Although thousands of acres have been treated each year, spanning both nonconiferous and coniferous communities, remarkably little is known about the impact of treatments on plant and animal communities, or about treatment impacts on intensity or severity of subsequent fires. Further, little is known about the pretreatment communities themselves: what plant associations are included? what is their extent on the landscape? to what degree have they been invaded by exotic species? Personnel from the Medford, OR office of the BLM, Oregon State University (OSU), and Southern Oregon University (SOU) gathered and analyzed data largely from oak woodlands, shrub lands, and chaparral in the Applegate Valley to answer these questions.
More!
See an overview of the BLM's fuels reduction program (PDF), including a map of treated areas (current as of 10/2006).
Also check out a summary of some lessons learned (PDF) from 10 years of monitoring vegetation response to fuels reductions in woodland and chaparral.
An interior valley of Southwest Oregon. Photo by Kendra Sikes.
Old-growth whiteleaf manzanita. Photo by D. Coen.
Above: Map of the study area within which most projects are located. Produced by Eric Pfaff.
Page by Olivia Duren. Updated 1/2008.
Above: Madia flowers in front of Oregon white oak. Photo by D. Coen.
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Responses of chaparral and oak woodland plant communities to fuel reduction thinning treatments in SW Oregon
Dr. Pat Muir and Dr. Paul Hosten, Principal Investigators
