Publications - Oak and chaparral and fuels management in SW Oregon

A landscape view of southwest Oregon chaparral and conifer communities. Photo K. Sikes.

Publications

This page will be updated with new documents as they are published.

Posters and Presentations

Like no other: southwest Oregon chaparral and the challenge of conservation (PDF)
Olivia Duren
Oregon State University
Presented to the Oregon Native Plant Society, Siskiyou Chptr., Ashland, OR, 10/21/2010.

Surprising new knowledge has recently been uncovered about the ecology and shrub species biology of southwest Oregon chaparral, suggesting that this plant community is unique in the Klamatha ecoregion and in the west . But people live here, too – how do we meet the challenges of chaparral conservation in a built landscape?

Fuel-reduction treatments: Treatment types and a landscape strategy to achieve restoration and a fire-safe landscape in the Applegate valley of southwest Oregon (PDF)
Al Mason , Paul Hosten, Greg Chandler, and Jerry Serabia
Ashland Field Office, Medford District Bureau of Land Management, Medford, Oregon

The Ashland BLM Field Office has actively pursued fuel reduction since 1996. Treatment types include hand-cut pile and burn (HPB), mechanical mastication, and prescribed fire. Fuels treatment objectives can include fuel hazard reduction, forest health, fish and wildlife habitat enhancement, restoration (grass, shrub, and oak woodland communities), and commercial thinning. This poster describes some of the processes and tools utilized to achieve fuel hazard reduction objectives on the landscape and within the Wildland Urban Interface.

Lessons learned after 10 years of fuel-reduction and monitoring in woodlands/chaparral of the Lower Thompson creek, Applegate valley, southwest Oregon (PDF)
Greg Chandler, Paul Hosten, and Al Mason
Ashland Resource Area, Medford District Bureau of Land Management, Medford, Oregon

The woodland/chaparral of Lower Thompson creek are patchy with varied domination by whiteleaf manzanita, buckbrush, and multi-aged Oregon white oak. Prior to fuels reduction, vegetation usually consists of 100% woody canopy cover by 6 to15 foot shrubs and trees, with a sparse understory dominated by blue wildrye, Idaho fescue, cats ears, and blue-dicks. The objective of fuel-reduction initiated in 1996 was to create low-fuel Oregon white oak savanna to facilitate a fire-safe landscape. This poster describes the site impacts of the fuel-reduction program, how vegetation has developed since treatment, and adaptations to the program that have resulted from ongoing monitoring and analysis.

Vegetation response to wildfire across an elevation gradient in Southwest Oregon (PDF)
Linda Mazzu and Paul Hosten
Medford District Bureau of Land Management, Medford, Oregon

Recent wildland fires on Medford District Bureau of Land Management (BLM) land offer an opportunity to compare vegetation recovery of plant communities found in southwestern Oregon along an elevational gradient. The Quartz fire (2001) and Squires Peak fire (2002) represent the lower elevation plant communities (chaparral, oak woodland, and mixed conifer). The Timbered Rock Fire (2002) is intermediate in elevation and is comprised more of mixed hardwood-conifer and white fir communities. The higher elevation portion of the Biscuit Fire (2002) that burned on Medford District is dominated by white fir and tanoak communities. Vegetation response to wildfire was examined by comparing burned and unburned plant communities using paired point cover transects and repeat photos. Response in re-seeded versus unseeded areas within each of the fires was also compared.

Effect of grass seeding on native and exotic vegetation following fuel-reduction treatments by mastication and burning (PDF)
Celeste Coulter, Darlene Southworth, and Paul Hosten
Southern Oregon University and Medford District Bureau of Land Management

Brush mastication has been widely used throughout the Applegate Valley of southern Oregon to reduce fuels in wildland-urban interfaces dominated by fire-suppressed chaparral. This study examines the effects of prescribed fire and seeding of native bunchgrass in brush masticated chaparral on (1) germination and establishment of native grasses, (2) control of exotic annual grasses and forbs, and (3) maintenance of native species richness.

Theses

Stand Structures of Oregon White Oak (Quercus garryana) Woodlands and their Relationships to the Environment in Southwestern Oregon (PDF)
Laurie Gilligan
Oregon State University, Masters thesis, 2010.

Large areas of non-coniferous communities in southwestern Oregon are thinned to reduce fire hazard and accomplish ecosystem restoration, under the assumption that current fuel loads are unnaturally high. Although Oregon white oak (Quercus garryana) woodlands are a characteristic landscape component in this region, little is known about their current or historical stand structures. Managers lack information on which to base restoration-focused fuel reduction prescriptions. I inventoried 40 Oregon white oak dominated woodlands across 2 study areas in southwestern Oregon, and describe here their stand characteristics and age structures. I also assessed whether these varied systematically with site conditions or recorded fire history. This new information may assist land managers’ development of regionally-specific models for restoration of oak woodlands on the public lands of southwestern Oregon, where fuels reduction is also a priority.

Chaparral History, Dynamics, and Response to Disturbance in Southwest Oregon: Insights from Age Structure (PDF)
Olivia Duren
Oregon State University, Masters thesis, 2009.

The fire ecology of southwestern Oregon interior valley chaparral is virtually unknown and the assumptions guiding the need for and design of fuels treatments are based on extrapolations from other ecosystems. What age structures and fire regimes characterize southwestern Oregon interior valley chaparral, and how has chaparral responded to fire suppression? Are current fuel treatments likely to accomplish restoration of these systems? To what extent are community processes in southwestern Oregon interior valley chaparral, which represents the northernmost extent of the chaparral range, comparable to California chaparral and other Mediterranean-climate obligate-seeder communities? I studied patterns in age structure of two obligate-seeding chaparral shrubs, sticky whiteleaf manzanita (Arctostaphylos viscida) and buckbrush (Ceanothus cuneatus), and assessed relationships with environment, grazing, and fire. My objective was to generate more knowledge about this understudied ecosystem to assist land managers’ development and assessment of management objectives.

Landscape-scale Patterns of Grassland, Shrubland, and Woodland Vegetation in Relation to Environment and Disturbance (PDF)
Eric Pfaff
Southern Oregon University, Masters thesis, 2007.

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.

Impacts of Fuel Reduction Thinning Treatments on Oak and Chaparral Communities of Southwestern Oregon (PDF)
Keith Perchemlides
Oregon State University, Masters thesis, 2006.

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.

Books

"Oak Woodland and Savanna Restoration."
Hosten, P.E., Gene Hickman, Frank Lake, Frank Lang, and Dave Vesely

In RESTORING THE PACIFIC NORTHWEST. The Art and Science of Ecological Restoration in Cascadia
Dean Apostel and Marcia Sinclair, Editors. Island Press.

Merit Award winner from the American Society of Landscape Architects!

From the publishers: "The Pacific Northwest is a global ecological "hotspot" because of its relatively healthy native ecosystems, a high degree of biodiversity, and the number and scope of restoration initiatives that have been undertaken there. Restoring the Pacific Northwest gathers and presents the best examples of state-of-the-art restoration techniques and projects. It is an encyclopedic overview that will be an invaluable reference not just for restorationists and students working in the Pacific Northwest, but for practitioners across North America and around the world.".

Journal Articles

Several articles are in review. Please check back for new postings! (See also related journal articles by other groups.)

Duren, OC, and PS Muir. 2010. Does fuels management accomplish restoration in southwest Oregon, USA, chaparral? Insights from age structure. Fire Ecology 6: 76-96. (link to journal with free full pdf)

Fuels management is often intended to both reduce fire hazard and restore ecosystems thought to be impacted by fire suppression. Objectives to reduce fire hazard, however, are not compatible with restoration in many vegetation types. Application of ecologically incompatible treatments to poorly understood ecosystems can drain management resources and contribute to ecosystem degradation. Extensive areas of chaparral on Bureau of Land Management lands in southwest Oregon, USA, are annually targeted for fuels treatment. However, the fire ecology of this ecosystem is not well understood and the assumptions guiding treatment need and design are based on extrapolations from other ecosystems. We studied patterns in age structure of two obligate-seeding chaparral shrubs, sticky whiteleaf manzanita (Arctostaphylos viscida Parry) and buckbrush (Ceanothus cuneatus [Hook.] Nutt.) and assessed relationships with environment, fire, and potential livestock disturbance. Results indicate that chaparral of obligate seeding species encompasses a wide range of structures and responses to environment and fire throughout its range. While Mediterranean climate obligate-seeding shrub populations are typically even-aged, most stands unburned >30 yr were uneven-aged due to both recruitment in the absence of fire and to persistence of shrubs that predated the last fire. Fire suppression does not seem to have altered chaparral structure or fire severity, and current fuels treatments appear unlikely to reproduce stand structures observed in mature chaparral or in post-wildfire stands. Results underscore that effective fuels management should be both sensitive to regional variability and founded on ecosystem-specific data.

Coulter, CT, D Southworth, and PE Hosten. 2010. Prescribed fire and post-fire seeding in brush masticated oak-chaparral: consequences for native and non-natve plants. Fire Ecology 6: 60-75. (link to journal with free full pdf and appendix)

In fire-suppressed oak-chaparral communities, land managers have treated thousands of hectares by mechanical mastication to reduce hazardous fuels in areas of wildland-urban interface. The chipped debris, which decomposes slowly, can be burned to minimize wildfire hazard. The question is whether controlled burning of masticated debris results in loss of native plant species richness and abundance, allowing for gains in non-native species. We examined the response of vegetation to the seasonality of prescribed fire and to post-fire seeding in mechanically masticated oak-chaparral communities in the Applegate Valley of southwestern Oregon, USA. At the landscape level, treatments did not differ. At the site level, response of native and non-native species varied by site and treatment. Following prescribed fire, native species decreased in cover and increased in species richness; non-native species increased in cover and in species richness. Seven species that were not observed on pre-treatment plots appeared after burn treatments. Non-native annual grasses and forbs increased following both spring and fall burns. Among native species, annuals declined in cover while perennials increased slightly. Both annual and perennial natives increased in species richness following burn treatments. Community patterns at the site scale changed following all treatments. Seeded bunchgrasses, Lemmon’s needlegrass (Achnatherum lemmonii [Vasey] Barkworth), California brome (Bromus carinatus Hook. and Arn.), blue wildrye (Elymus glaucus Buckley), and Roemer’s fescue (Festuca idahoensis Elmer ssp. roemeri [Pavlick] S. Aiken), successfully established following fall prescribed fires, but not following spring prescribed fires or in unburned controls. Post-fire seeding and subsequent increased bunchgrass cover correlated with decreased non-native species. Prescribed low severity fire followed by post-fire seeding during the wet, cool season is a viable tool for introducing native bunchgrasses while controlling non-native species in mechanically masticated oak-chaparral in southwestern Oregon.

Sikes, KG, and PS Muir. 2009. A comparison of the short-term effects of two fuel treatments on chaparral communities in southwest Oregon. Madrono 56: 8–22. (link to journal, requires subscription)

ABSTRACT. Fuel treatments to reduce fire danger are being applied to public lands throughout the western United States, affecting significant acreage at considerable expense. This study compares the short term effects of two fuel treatment methods, shrub mastication and ‘‘hand cut, pile, and burn’’ (HPB), on chaparral communities in southwestern Oregon. Ceanothus cuneatus dominated the study sites where permanent paired plots were established on either side of treatment-control boundaries. Over a
two year period, we recorded all vascular plant species within each treatment or control plot, along with an abundance class for each species. The effects of treatment on species composition and abundance of forbs and graminoids, overall as well as by plant trait group, were surprisingly small. Time since treatment, 1 yr or 2 yr, had a stronger effect on species composition than did treatment
method. Species abundance and richness were greater in the first year after treatments than in the second year or in controls. In the second year, after both types of treatments, species abundance and richness were reduced, while after mastication treatment, these measures were lower than in control areas. The HPB treatment had a greater effect on plant communities than did mastication, due, at least in part, to the presence of fire rings from burned piles. Compared to their surrounding treated plots, fire rings had greater proportions of both annuals (95% versus 71%) and introduced weeds (35% versus 21%) in the second year after treatment. Ceanothus germination was stimulated in fire rings but also occurred in most plots, including controls. Both types of treated areas had more Ceanothus seedlings than their controls. Short term evidence suggests that the HPB treatment may lead to an increase in weedy and exotic species and the mastication treatment may reduce species diversity. The HPB treatment may also increase native species diversity by allowing fire-cued species to establish. Additional monitoring over time is needed to assess longer term treatment consequences for these northern chaparral communities.

Key Words: Burn piles, Ceanothus cuneatus, chaparral, fire management, fuel reduction, shrub mastication.

Perchemlides, KA, PS Muir, and PE Hosten. 2008. Responses of chaparral and oak woodland plant communities to fuel reduction thinning in southwestern Oregon. Journal of Rangeland Ecology and Management 61: 98-109. (link to full PDF)

ABSTRACT. Fire suppression has led to large fuel accumulations in much of the United States. In response to concerns about associated wildfire hazards, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. While reductions in cover by woody vegetation seem likely to cause changes in herbaceous communities, few published studies have reported on consequences of such treatments for native or exotic plant species. We compared vegetation and abiotic characteristics between paired thinned and unthinned chaparral and oak woodland communities of southwestern Oregon 4 to 7 years post-treatment, and contrasted impacts of manual vs. mechanical treatments. Herbaceous cover increased on thinned sites, but species richness did not change. Herbaceous communities at thinned sites had an early-post-disturbance type of composition dominated by native annual forbs and exotic annual grasses; cover by annual species was nearly twice as high on treated as on untreated sites. Absolute and proportional cover of native annual forbs increased more than any other trait group, while exotic annual forbs and native perennial forbs declined. Exotic annual grass cover (absolute and proportional) increased while cover by native perennial grasses did not. Shrub re-establishment was sparse in thinned areas, probably due to a lack of fire-stimulated germination. Manual and mechanical treatment impacts on abiotic site conditions differed, but differences in their impacts on vegetation were not statistically significant. Fuel-reduction thinning may have some unintended negative impacts, including expansion of exotic grasses, reductions in native perennial species cover, persistent domination by annuals, and increased surface fuels. Coupled with sparse tree or shrub regeneration, these alterations suggest that ecological state changes may occur in treated communities. Such changes might be mitigated by retaining more woody cover than is currently retained, seeding with native perennials after treatment, or other practices; further research is needed to inform management in these ecosystems.

Key Words: Arctostaphylos, Ceanothus, exotic annual grasses, mastication.

Page by Olivia Duren. Updated 10/2010.