Model analysis of post-fire management and potential reburn fire behavior

Area of Science:

• Forestry and Fire Ecology
• Post-wildfire Management
• Ecosystem Services

Background:

• Wildfires are increasingly characterized by large areas with high densities of dead trees.
• Post-fire tree harvesting (salvage logging) is used for economic reasons and to reduce future fuel hazards.
• The effectiveness of salvage logging in altering reburn fire behavior and its impact on ecosystem services remain unclear.

Purpose of the Study:

• To simulate the effects of different salvage logging intensities on future fuel hazard and reburn fire behavior.
• To assess the impact of salvage logging on soil fire effects and coarse woody debris (CWD) dynamics.
• To evaluate the tradeoffs associated with post-fire harvesting in the context of ecosystem functions.

Main Methods:

• Utilized observed post-fire snag structure from four high-severity burn scars in the Western U.S.
• Initialized simulation studies comparing untreated controls with intensive and intermediate salvage harvest treatments.
• Modeled future coarse and fine woody fuel loads, reburn fire behavior, and soil fire effects.

Main Results:

• All treatments, including harvested stands, exhibited extreme fire behavior for several years, indicating limited impact on reburn fire management.
• Harvested stands showed reduced soil heating and smoldering duration compared to controls, attributed to lower predicted coarse woody fuels.
• Higher pre-treatment snag basal areas in harvested stands helped maintain CWD within a range beneficial for ecosystem functions.

Conclusions:

• Salvage logging may not eliminate severe fire behavior post-wildfire, despite fuel reduction.
• Reductions in coarse woody fuels through harvesting can mitigate some soil fire effects.
• Post-fire harvest decisions require careful consideration of regeneration, local conditions, snag fall, and potential reburn effects.