Sustain Our Nation's Forests and Grasslands

Using FIA to understand the post-fire environment: A PNW–RMRS collaborative

Photo: Workers use measuring tapes, other tools to inspect burned fir trees.
Forest Inventory and Analysis crew members inspect fir trees that have been charred by wind-driven flames 30 feet up from the base. Forest Service photo by Jeremy Fried.

OREGON—Rocky Mountain Research Station research silviculturist Terrie Jain recently joined Pacific Northwest Research Station research foresters Jeremy Fried and Jason Barker for two days of FIA field crew training in areas burned by the 2017 Eagle Creek Fire in Oregon’s Columbia Gorge. Accompanied by 15 Forest Inventory and Analysis field crew members, they made the trek to this fire-scarred Douglas-fir forest to promote engagement around protocols developed for the Fire Effects and Recovery Study, an important element of PNW’s fire and fuels research portfolio.

Since 2002, Jain and Fried have been developing and refining protocols to assess the post-fire environment on FIA plots where precise ground measurements were collected before fires occurred. They have long recognized that FIA’s spatially balanced sampling framework and its consistent, quality-assured pre-fire data make a compelling case for focused measurements and analysis to better understand both what fire leaves behind and how this is influenced by the interaction of pre-fire forest structure and fire weather. PNW-FIA reinvigorated FERS in 2016, implementing the FERS protocol on all FIA plots during visits to collect standard FIA data—if the plot happened to fall within a burn perimeter in the past two years.

The recent training expanded the cadre of FIA field crews skilled in the FERS protocol. Some of the measurements can be challenging to make correctly amid the chaotic and heterogeneous aftermath of a mixed-severity wildfire. These include surface char class cover estimates, depths of pre- and post-fire litter and humus, and indications of fire behavior seen in bole char and crown scorch and consumption.

“You get to be the detectives when solving these puzzles,” Jain enthused to the crews. “These rocks were fractured by intense heat, and the deeply charred soil is now orange, with all organic matter burned away—something that happens only near stumps and large down wood that generate sustained, elevated temperatures as they burn. Look how wind-driven flames swept upward from this spot to scorch the canopy of those maples 100 feet down the hill and charred these firs 30 feet up the bole!”

Fried, who has led FERS since it began in 2003, explained that data collected earlier is now being analyzed by Jason Barker in an effort to build better models for predicting tree mortality. Barker reported that effects of fire on soils, as assessed by FERS, are turning out to be important predictors of tree mortality for some species. Fried and Jain are formulating plans to use empirical data produced by FERS to test the efficacy of fuel treatments they are modeling under the BioSum analysis framework in the Forest Vegetation Simulator. The many stories that can be told and questions resolved using this unique and growing dataset are a powerful motivator for both researchers and field data collectors.

Acting quality assurance lead Jessica Deans explained it this way, “This two-way knowledge exchange between researchers and field staff, engaging in person at the scene of fire effects, really brings this to life—it’s energizing, motivating and terrific for ensuring high-quality, repeatable data suitable for supporting decisions and framing policies.”

Earlier FERS studies were enabled by funding support from USFS Region 5 and the Western Wildland Environmental Threat Assessment Center. Current work to build better models for predicting tree mortality is part of a study funded by the Joint Fire Sciences Program and led by PNW–RMA research ecologist Andrew Gray.