Restoring pattern to frequent fire forests with variable-density thinning

Interesting lecture coming up. If anyone here can go, please post a report on what you see and hear.

Restoring pattern to frequent fire forests with variable-density thinning: implementation and initial outcomes

Thursday, May 2, 2019
1:00 PM 2:00 PM

University of California-Davis Asmundson Hall “Big Hannah” (Room 242) Davis, CA

In the abstract for the lecture, I highlighted text that demonstrates the outcomes of such thinning. These treatments are needed throughout the west, including spotted owl habitat. I am mystified why anyone would oppose such management and claim it is “industrial logging” designed to line the coffers of timber companies.

Abstract: Historical forests shaped by fire were highly heterogeneous at the within-stand scale, with dense groups of trees and individual trees interspersed with numerous small gaps. Stem maps from research plots on the Stanislaus National Forest dating to 1929 show that prior to any logging, canopy cover was 45% and over 20% of the area within stands was in canopy gaps where shrubs were abundant. As a result of past logging and fire exclusion, the contemporary stands were denser and more homogeneous, with no gaps and very low shrub cover. To improve resilience to disturbances such as wildfire or drought, while better balancing the needs of associated plant and animal species, we utilized the historical structure as a guide to a ‘variable density’ thinning prescription, comparing this with a standard thinning to an even tree crown spacing, and an unthinned control. Half of the units were then treated with prescribed fire. Mechanical thinning removed 40% of the basal area, and by favoring pines over fir and cedar, produced a species composition similar to the historical reference condition. Variable thinning enhanced within-stand structural heterogeneity and did so at spatial scales similar to heterogeneity found in historical stands. Both thinning treatments experienced significantly less tree mortality during the recent drought than unthinned controls. In addition, understory shrubs and grasses are already much more abundant, especially where thinning was followed by prescribed fire. While still early, it is our hope that the variable density thinning with prescribed fire treatment will not only be more resilient to future wildfires and droughts, but also produce conditions suitable for a greater diversity of species. [emphasis added]

12 thoughts on “Restoring pattern to frequent fire forests with variable-density thinning”

  1. When I last worked on a marking crew, it was me who always found spots to place “clumps and gaps”, within the cutting units. With a nod to the GTR-220, we were directed to look for suitable spots. It was far easier to find clumps that would be left intact, than to find a gap, and make it larger. Of course, many gaps were flagged to be outside of the units, anyway.

    You can see two of those clumps in this cutting unit I led the crew through. Amador RD Eldorado NF,-120.3314637,287m/data=!3m1!1e3?hl=en

  2. Just received this press release from the University of Nevada, Reno, about a study in the works involving Dr. Knapp. The list of treatments is interesting….

    April 18, 2019

    Forest management research to help fight effects of climate change

    Forests and their ecosystems face increased threats to health as temperatures rise

    RENO, Nev. – Prolonged drought, landscape-level bark beetle mortality, and catastrophic wildfire have been increasing in frequency, extent, and severity over the past few decades, and western forests will be increasingly stressed as temperatures rise and climate change effects intensify.

    Leading a team of scientists and forest managers, Sarah Bisbing, a forest ecology assistant professor and researcher from the University of Nevada, Reno, is building a Sierra Nevada-wide study, the Sierra Nevada Adaptive Management Experiment, known as AMEX, to identify alternative forest management treatments that will improve conifer forest resistance and resilience to climate change.

    Bisbing, a faculty member in the Department of Natural Resources and Environmental Science, received a $2.8 million grant from CAL FIRE’s Forest Health Grants Program to implement this large-scale, replicated experiment in collaboration with state and federal land management agencies.

    Over four degrees latitude from the northern to southern Sierra Nevada (Shasta to Tulare counties), this long-term, multi-decade study will compare treatments representing fundamentally different climate change impact scenarios and a suite a potential approaches forest managers may take to mitigate impacts on the ecological, economic and social services provided by forest ecosystems.

    The project is designed to support silviculture research, which is applied forest ecology or the act of managing a forest to meet a desired set of ecological, economic and social conditions.

    “This research will help inform what forest managers will do in the long run to increase carbon sequestration, combat drought mortality, and make forests more resistant and resilient to catastrophic wildfires and insect damage,” Bisbing said. “Climate change is and will be increasing the severity of ecological disturbances in forests, which will not only have devastating impacts on forest ecosystems but also turn these carbon sinks to carbon sources, leading to increases in the release of carbon into the atmosphere. This study will guide forest managers as they build resilience and resistance to those disturbances and attempt to mitigate the impacts of climate change on forest ecosystems.”

    Ongoing and predicted impacts to forests include regeneration failures, shifts in species’ ranges, drought mortality, and increasing severity of disturbances such as bark beetle outbreaks and/or fire. These changes are creating uncertainty in how forests will function in the future and concerns around sustaining ecosystem goods and services.

    The AMEX project is designed to be a long-term assessment of the effectiveness in common and novel silvicultural tools for climate change mitigation and to track forest response under changing conditions. Multiple treatments will be implemented, as no single activity will reduce these threats, and research will help identify solutions and target structures to support climate change mitigation while also informing seed zone regulations for reforestation efforts.

    All project actions will lead to immediate short-term carbon sequestration through release of large-diameter trees and long-term carbon storage through reforestation efforts and regular maintenance of proposed conditions. Forest health improvement treatment types are defined as resilience, resistance, and transition treatments and include fuels reduction, pest management, biomass utilization and reforestation coupled with mechanical treatments to provide diversity in species, age classes and structures at the landscape and regional scales.

    Resilience treatments closely mimic forest structure under historic fire conditions and are designed to prepare the forest for disturbance by creating tree stand conditions that will help recovery of pre-disturbance composition and structure.

    Resistance treatments are aimed at reducing fuel loading and will prepare the forest to resist a disturbance by creating stand structure that is open, park-like and forces fire to stay on the ground.

    Transition treatments will help the forest adapt to changing climate, representing the scenario where resistance and resilience treatments are not effective and the forest cannot recover without intervention. Treatments mimic a disturbance that fundamentally changes the composition and structure of the forest, requiring foresters to plant species better adapted to the new conditions of the climate change-impacted system.

    Project activities will support a suite of ecosystem services across the western Sierra Nevada by creating forest age and plant community diversity at multiple scales, including:

    Diverse age stands will help facilitate wildlife movement via patch diversity and intact corridors while supporting habitat for a wide range of species.

    Resistance treatments, reductions in basal area and removal of understory fuels will support increased diversity in the understory plant community and associated herbivores.

    Resilience treatments will create the greatest compositional and structural diversity, supporting a wider range of plant and animal species under both current and future conditions.

    Transition treatments are aimed at insuring continued forest cover under future conditions, maintaining carbon sequestration over a 100-year rotation while also providing for continued forest cover for wildlife.

    Fuels reduction activities will have a wide-reaching impact on watersheds and downstream users by reducing sedimentation, maintaining water quality and providing a continued source of upland water for downstream users.

    Biomass removed via harvest will be stored long-term in wood products produced by local mills, such as Sierra Forest Products in the southern Sierra Nevada.

    The study was designed by Professor Rob York and Rick Satomi of U.C. Berkeley and Bisbing. It is based on the national Adaptive Silviculture for Climate Change program led by Linda Nagel at Colorado State University. Project collaborators include Jim Kral and Jason Poburko of the California Department of Forestry and Fire Protection and Eric Knapp and Malcolm North of the U.S.D.A. Pacific Southwest Research Station.

    Bisbing specializes in forest ecology, silviculture, forest stand dynamics, forest landscape genetics and global change ecology. She joined the University of Nevada, Reno’s College of Agriculture, Biotechnology and Natural Resources in Fall 2017 after four years as an assistant professor at Cal Poly – San Luis Obispo. She has a bachelor’s and master’s in forestry from the University of Montana and a doctorate in ecology from Colorado State University. Details of the project can be found at

    Funding for this project was provided by the California Department of Forestry and Fire Protection as part of the California Climate Investments Program.

  3. This sounds like a good project, but one minor quibble.

    “Treatments mimic a disturbance that fundamentally changes the composition and structure of the forest, requiring foresters to plant species better adapted to the new conditions of the climate change-impacted system.”
    But if we don’t know what the changes are, how are we supposed to figure out which species are “better adapted”? Even if we understood adaptation by forest trees, which we really don’t (understand the mechanisms of) within species.

  4. Steve: “I am mystified why anyone would oppose such management and claim it is “industrial logging” designed to line the coffers of timber companies.”

    Nobody has disagreed yet. If we are really limiting this restoration to “thinning” areas with “past logging and fire exclusion,” I could see potential for a lot of agreement. Where there might be less agreement is areas without the “past logging” part or proposing logging instead of thinning.

    • I hear you, Jon, but even stands where there hasn’t been past logging may benefit from careful thinning — which is a form of logging. Industrial logging? Sure, profit is a motive for loggers and mills. Maybe that’s part of the objection — profit.

    • I think the problem is that some very smart people made up emotionally resonant names for things they don’t like, and those names have no physical meaning.

      Say “industrial logging”- what is the difference between that and thinning? Diameter limits? Diameter limits as a proportion of the largest trees in the stand? Saleability? Which then makes one think “if we could sell small trees for CLT or chips or pellets, would that make every thinning “industrial”? Seems like we might need terminology that sheds light rather than heat (so to speak re: pellets).

  5. I think there are three main drivers of objections to vegetation management: building roads, removing big (usually old) trees, and impacts on at-risk or game species. I wouldn’t include profit per se.


Leave a Comment

Discover more from The Smokey Wire : National Forest News and Views

Subscribe now to keep reading and get access to the full archive.

Continue reading