Comparing Passive and Active Postfire Forest Management Under a Changing Climate

Photo Credit

Morris Johnson, USDA Forest Service

Extent of study sites for the project across the western United States.

Morris Johnson, research fire ecologist with the Pacific Northwest Research Station, is working on an innovative project to compare passive versus active postfire forest management to help ensure the success of the agency’s 2022 10-year Wildfire Crisis Strategy.

Restoration activities such as salvage logging after large wildfires can be contentious forest management issues on federal lands. Johnson is partnering with National Forest System staff to establish long-term monitoring projects that will quantify the short- and long-term effects of passive and active treatment effects in severely burned forests.

The forest managers that Johnson is working with identified high-priority questions that would help them sort through options for postfire restoration: 

1. What are the effects of active and passive management on forest structure, the amount of dead woody debris (or loadings) as potential fuel for wildfire, tree seedling survival, and shrub cover? 
2. Do treatments affect overall shrub and seedling regeneration and promote invasion by non-native species? 
3. Do salvage operations positively or negatively affect rates of natural tree regeneration?

This project provides a unique example of coproduction between researchers and managers. As the postfire monitoring leader on National Environmental Policy Act (NEPA) postfire restoration interdisciplinary teams, Johnson participates in the full cycle of NEPA project planning for more than a dozen postfire projects.

“I am working closely with national forest staff so that we can study different management options and better understand which option will help them achieve their goals,” he said.

The research sites included in this study are part of a larger effort to establish coproduction relationships with forest managers throughout the Western United States. Researchers and managers collaborate at the early stages of study development to ensure that research objectives align with management research questions and issues. Site selections, research questions, and experimental design for this project were all completed in collaboration with local forest managers. 

The information produced by this project will help forest managers plan management treatment interventions to effectively steer pre- and early-tree-regrowth, or early-seral, trajectories toward desirable future conditions. It will also evaluate whether accumulation of dead woody fuels and shrub regeneration hinders the reestablishment and survival of seedlings, deflecting the trajectory for forest succession and therefore preventing the accomplishment of long-term management objectives.

Photo Credit

Morris C. Johnson, USDA Forest Service

Mailani Carita, recent Oregon State University graduate, collecting data on the Boise National Forest (2024).

Photo Credit

Morris C. Johnson, USDA Forest Service

Cedric Burrell, an 1890 Land-Grant Institutions Wildland Fire Consortium student at Alabama A&M University, working on the Santa Fe National Forest postfire monitoring project (2024).

Objectives

• Establish a network of long-term postfire monitoring plots to achieve the following: 
  • Quantify the immediate (1 to 2 years after harvest) and long-term (>5 years) treatment effects of salvage logging on stand structural characteristics, fine and coarse woody fuel loadings, shrubs and herbaceous vegetation. 
  • Quantify early (<5 years) postfire seral woody fuel trajectories in several previous paired and complete randomized block design postfire restoration projects that were not purchased and subsequently were not treated. 
  • Use field data and the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) to simulate postfire dead woody fuel succession and snag dynamics. 
• Test two main hypotheses: 
  • Postfire logging would initially increase woody fuels relative to controls (unlogged stands) by transferring nonmerchantable woody debris (e.g., branches, twigs) from tree canopy to the forest floor. 
  • Postfire logging reduces long-term fuel loadings and future fire severity (reburn) by extracting the source/contributor to woody fuel loadings (snags).

Expected Products

• Monitoring and simulation data that will help managers prioritize areas for restoration treatments near critical habitats and evaluate when important ecological thresholds might be exceeded. 
• Improved scientific basis for prioritizing postfire restoration treatments, reforestation strategies, and fuel management strategies. 
• Information about potential postfire future stand structural conditions. For example, projecting postfire woody fuel succession may alert managers and policy makers to the urgency of the postfire fuels crisis and identify areas in need of active management. 
• Information about the use of postfire management treatments (e.g., prescribe fire, salvage logging) to increase forest resilience to subsequent wildfire, biotic stressors and expected changes in climate.

Expected Outcomes

This project will strengthen a collaborative partnership between land managers and scientists, improve the science of postfire management decision-making, and fill a critical science knowledge gap. Long-term monitoring will evaluate whether accumulation of dead woody fuels and shrub regeneration hinders the reestablishment and survival of seedling regeneration, deflecting the trajectory for forest succession and therefore preventing the accomplishment of long-term management objectives (reforestation).

Metrics of Success

Project deliverables will help forest managers plan management treatment interventions to effectively steer early-seral trajectories toward desired future conditions.

Keywords: Postfire recovery, forest resilience, harvest, regeneration, coproduction, BIL.