Cleansing fire: Restoring Washington’s forestland

Cleansing fire: Restoring Washington’s forestland
The state Department of Natural Resources has released its report on a two-year pilot prescribed burn project directed by the state legislature that points to this strategy as an effective way to reduce fuel loads with minimal impact on air quality. Photo: TJ Martinell

In 2016, the Washington state legislature directed the state Department of Natural Resources (DNR) to conduct a prescribed burn pilot project to explore the possibility of using it more often to restore unhealthy Washington forestland. DNR has now released a report on the project’s conclusions, which strongly indicate that prescribed burning at the right time of the year can be highly effective at removing fuel loads and small-diameter trees, with minimal effects on local air quality and older, fire-resilient tree stands.

The report represents one of several ongoing efforts to increase controlled burns, which in the past have been restricted by various regulations and policies as well as public concerns over smoke generated by these fires.

In the report, DNR acknowledges that “more than 100 years of fire suppression and land management practices have severely degraded Eastern Washington’s fire-adapted dry forests. Without the regular, low-intensity fires that created their open stand structure and resiliency, tree density has increased and brush and dead fuels have accumulated in the understory. The impact of these changes in combination with longer fire seasons have contributed to back-to-back record-breaking wildfire years, millions spent in firefighting resources and recovery, danger to our communities, and millions of acres of severely burned forest.”

Washington Forest Protection Association Government Affairs Director Cindy Mitchell told Lens that the goal eventually is to have forestlands that can once more rely on a natural fire regime to stay healthy. Until then, those forests need active management in order to be restored to their previous condition, though “not as much on private land because there’s (already) a continuous management cycle.

“We want and support a variety of tools to reduce the fuel loadings in the forests, and prescribed burnings is definitely one of those,” she said. “Everybody’s minds are on the forest fires.”

She added that “for the most part, the objective is to put the fire out really quickly. If we have that objective…you’re going to need to pay attention to the overgrowth.”

For the pilot, DNR collaborated with 20 other government agencies and private groups, including the state Department of Ecology, the U.S. Forest Service, the Nature Conservancy, the University of Washington, the Washington Resource Conservation and Development Council, Cascadia Conservation District and Chelan County Fire District #3.

The pilot involved over a dozen burn projects between 2016-17 in central and eastern Washington. As part of each project, air quality levels were monitored, and fuel loads were measured to determine how much the flames reduced their levels.

One of the hurdles for controlled burnings has been air quality stipulations that require morning-of approval for a burn to occur. However, the 2016 state law ordered DNR issue a 24-hour burn permit. During that time, the land managers overseeing the projects requested approval 73 times; 61 of the requests were approved, and only two would have been denied the morning of, according to the report.

The report further concluded that “smoke from prescribed fire activities had limited impacts to air quality in communities and generally fell within acceptable ranges as established by federal regulations. This was true of all locations except one, where prescribed burning operations on a project not associated with the pilot…resulted in several days of smoke impacts, including two days where air quality levels likely exceeded 24-hour average standards to a level deemed ‘unhealthy for sensitive groups.’”

Mitchell said that it’s critical to differentiate smoke from megafires that this year covered much of the state, compared to the smoke emitted by controlled burns. “How do you want the smoke? You want it in a controlled, careful setting, or do we have these catastrophic fires. When they become unstoppable, they put out more smoke and they cause the type of damage to the soil where it becomes impenetrable by water.”

Another finding in the report was that “there was no significant difference in air quality and smoke impacts between using a 24-hour burn approval process versus the current policy of day-of burn approval. DNR’s internal analysis of its smoke approval process found that, during the more stable fall burning window, 24-hour advance predictions held better than in the more historically unsettled spring season. That said, burning and assessment opportunities were limited by very early fall rains and our long, wet spring.”

One of the key objectives of a controlled burn is to remove fuel loads that cover forest floors and are a major contributor to wildfire intensity.

The report concluded that the projects carried out during the fall were highly successful in that regard. According to a supplemental report put out by the U.S. Forest Service’s Pacific Northwest Research Station that examined six of the burn sites, those fires removed 62-86 percent of total surface fuels (Appendix C of the report). In the springtime, the burns consumed significantly less, between 12-22 percent.

“A next step to improving fuel consumption predictions should focus on modeling consumption of these dense forest floor fuels that burn under smoldering conditions,” the supplemental report stated. “This will provide improved duff (fuel) consumption prediction for inputs into smoke modeling systems that will enhance predictions of potential low buoyant smoldering smoke air quality impacts.”

In addition to costs of fire suppression, reduced air quality and the threats posed to local communities, megafires can also consume older forests that are otherwise resilient to normal wildfires as well as tree stands suitable for virtually all timber products – though there are ongoing efforts to carve out commercial value for small-diameter trees with cross-laminated timber.

However, DNR’s report noted “higher percent mortality in small diameter understory trees and low mortality in mature trees,” concluding that “understanding the conditions in which small-diameter trees may be killed using prescribed fire, but where impacts to mature trees are limited may be key using prescribed fire as a restoration and fuels reduction tool.”

Another apparent goal achieved during the project was public outreach in communities impacted by the controlled burns. The community meetings included a presentation by U.S. Forest Service Research Lab Ecologist Dr. Paul Hessburg, who has testified previously about megafires at various state legislative committees in the 2017 legislative session.

According to the report, “while there was no formal study on smoke complaints due to time and resource constraints, anecdotal evidence from local organizations suggests that complaints and inquiries into smoke from prescribed burning activities declined over the duration of the pilot.”

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