USDA Forest Service

Pacific Southwest Research Station
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Ecosystem Processes

Sierra Nevada Ecosystems

Plumas Lassen Admin Study (PLAS)
Fire and Fuels Management, Landscape Dynamics, and Fish and Wildlife Resources: Study Design for Integrated Research in the Northern Sierra Nevada

Study Plan
Research Project Summary

The Research

photo taken by Claire GallagherThe impetus for these studies comes from the Records of Decision (RODs) for both the Sierra Nevada Forest Plan Amendment (SNFPA) and the Herger-Feinstein Quincy Library Group (HFQLG) Forest Recovery Act Pilot Project. The SNFPA Decision (both 2001 and 2004) specifically calls for a study related to the HFQLG Pilot Project to examine the effects of management-induced changes in vegetation on California spotted owls, their prey base, and their habitat.

Some response variables require study over large geographic domains, e.g. what many refer to as the landscape level, while other response variables are appropriately examined using smaller geographic domains, which will enable use of more standard experimental designs. We are relying largely upon observational studies. Although observational studies do not allow for the strength of inference that true experimental studies can provide, such efforts will make the most of extremely difficult experimental conditions (particularly at a landscape scale) and can provide important insights to allow for better understanding of the variables of interest.


This research is intended to help resolve persistent questions about the effects of vegetation-management actions upon wildland fire behavior, silvicultural goals, landscape dynamics, and old-forest-dependent species viability. The specific research questions are addressed in separate documents describing each of the five individual research modules. The main objectives of the integrated research program include:

  • Wildland Fire Behavior and Protection. How do silvicultural treatments change existing conditions of fuels and thus affect potential fire behavior and effects? Are specific combinations of defensible fuel profile zones (DFPZs) and subsequent area fuel treatments effective in reducing the extent and severity of wildland fires? Are realized fire management benefits consistent with hypothesized results in reducing fire risk and altering fire behavior?
  • Silvicultural Goals. Vegetation management activities applied across landscapes on the Plumas National Forest will include both fuels reduction thinnings and regeneration group selection silviculture. These management activities are anticipated to result in changes to forest structure in terms of stand density and canopy cover. What is the growth response of remaining trees after thinning? How do microclimate conditions change in areas where there were fuels reduction thinnings and resulting canopy cover reductions?
  • Landscape Dynamics. How do combinations of DFPZs, area fuel treatments, group selection, riparian protection standards, and species-specific protection measures affect landscape dynamics such as forest structure, composition, and succession at multiple scales of space and time?
  • Species Viability. How will old-forest-dependent species, particularly the California spotted owl and its prey base comprised of various species of small mammals, respond to changes in vegetation composition, structure, and distribution induced by the planned forest management regime? How is response to treatments manifested at the individual and population levels of biological organization?

The above four issues all entail a dynamic forest ecosystem that is subject to natural processes of growth and mortality as well as vegetation manipulation through management and uncontrollable forces of weather and climate. All components of a forest respond to the dynamic nature of a forest ecosystem (both natural processes and human-induced changes) through continual adaptation across the landscape over space and time.

We have developed individual research modules that address these primary research objectives. They are in detail in separate documents. They include:

  1. Forest structure. Research Project Summary
  2. Fuels, fire behavior, and fire effects. Research Project Summary
  3. Spotted owl responses. Research Project Summary
  4. Small mammal distribution, abundance, and habitat relationships. Research Project Summary
  5. Landbird distribution, abundance, and habitat relationships. Research Project Summary
Methods and design

Our current overall research strategy is constrained by the lack of controlled treatment assignments at the landscape scale. Some questions that we otherwise would have liked to address through a hypothesis testing manner, in order to maximize the strength of inference that could be drawn, we will not be able to do. Alternatively we will have to employ a more case history or observational approach, what some refer to as passive adaptive management, where we monitor response to the treatments that will be implemented over space and time as governed by typical land management operations conducted outside of a rigorous control-treatment experimental design. Under this method, pre-treatment data are collected, predictions of anticipated responses to treatment are generated, and the post-treatment response is assessed to test model predictions and evaluate treatments effects.

The specific research modules and their attending research plans (see separate documents) will elaborate on specific questions and design considerations.

Application of Research Results

The work imbedded in this study is part of a larger adaptive management program for the Sierra Nevada. We intend to maximize the value of what is learned through primarily what scientists refer to as passive adaptive management where we examine response to treatments using a case study or survey method. A strict "survey" will not have the ability to address the questions in an experimental manner. We are investigating portions of the Sierra Nevada's westside coniferous forest ecosystem that will be subject to management actions (i.e. fuels treatments and silviculture) and examining a set of alternative predictive models that represent competing hypotheses about how the system will respond. This approach acknowledges that the relationship between the chosen management action and the mechanism that affects the system is not perfectly precise. We know there will be sources of variation within the measured response variables that will be unexplained by the models. But with some ability to assess an array of predictive or explanatory variables control we will learn about ecosystem functioning by monitoring a selection of response variables and evaluating alternative ecosystem models to determine which ones provide the best fit to the observed responses.

A key feature of adaptive management is that actions be studied at the same scale as management is conducted. Some of the important National forest management activities today are carried out at the landscape scale. Moreover, certain key response variables cannot be addressed without adopting a landscape level of inquiry. Variables such as spotted owl population response (e.g. density of owls) across time and space, or fire behavior response to alternative landscape configurations of fuel treatments, are not possible to investigate without using large land units. To the extent that we can we will continue to try and understand how responses observed are manifested at different spatial scales including these large geographic units of interest.

research area map

The location for this study is on portions of the Plumas and Lassen National Forests, including much of the land base for the HFQLG Pilot Project within the westside coniferous forests. Figure 1 displays the original study area boundaries (in blue/thick line) and the boundary of the HFQLG Pilot Project Area (in black/thin line). The HFQLG Pilot Project includes approximately 2.5 million acres within the Lassen, Plumas, and Tahoe National Forests. The current study area includes selected watersheds within the Plumas National Forest and some locations on the Lake Almanor District of the Lassen National Forest. The target population of forest conditions is intended to be west slope conditions in the northern Sierra Nevada.


The researchers involved in this effort will work both as a team, examining the array of response variables in an ecosystem context, and as individual principal investigators addressing specific topics. Annual meetings will be held to review recent findings and guide subsequent coordination efforts. Annual reports, summarizing information from annual meetings, are available at the Sierra Nevada Research Center web site.

Findings will be published in peer-reviewed journals. These products will be prepared and submitted when the principal investigator determines that the results are ready for publication.

More detailed examination of the study data will be conducted at 5-year intervals, beginning in 2008. Principal investigators will work as a team to consider study results and make recommendations on continuing the effort. The entire research team will jointly issue a formal report on the research findings of the previous 5 years. This report will include recommendations for future work.

Lead Scientists/Collaborators

Stine, P.A.1; Keane, J.1; North, M.2; Stephens, S.3; Kelt, D.4; Van Vuren, D.4; Johnson, M.5; Geupel, G.6; Baldwin, J.7; Bigelow, S.1; Menning, K.3; Burnett, R.6; Howell, C.6

1USDA Forest Service, PSW Research Station
ph: (530) 759-1700
fax: (530) 747-0241

2USDA Forest Service, PSW Research Station
Sierra Nevada Research Center
c/o Department of Plant Sciences
University of California at Davis
Davis, CA

3Department of Environmental Science and Policy
University of California at Berkeley
Berkeley, CA

4Department of Wildlife and Conservation Biology
University of California at Davis
Davis, CA

5John Muir Institute
University of California at Davis
Davis, CA

6Point Reyes Bird Observatory
Bolinas, CA

7USDA Forest Service, PSW Research Station
Albany, CA

Publications and Reports
Plumas Lassen Annual Reports
2010 Presentations
2009 Presentations
2008 Presentations
Habitat Management

Stine, P., Landram, M., Keane, J., Lee, D., Laudenslayer, B., Weatherspoon, P., and Baldwin, J. 2002. Fire and fuels management, landscape dynamics, and fish and wildlife resources: An integrated research plan for the Herger-Feinstein Quincy Library Group Pilot Study Area.

Last Modified: Aug 29, 2016 10:57:21 AM