Wildfires impact air quality greater than prescribed burns


An analysis provided by the US Forest Service has concluded what many forestland owners and woodland managers already know: Prescribed burns have a lower impact on air quality while helping to prevent forest fires than catastrophic wildfires. The study, which measured particulate matter within communities near the fires and urban centers far from the fires, found that megafires subject more people and a broader area to smoke than controlled burns.

Prescribed or controlled burns are intentional, low-intensity fires that help manage forestlands by reducing the dangerous accumulation of combustible fuels like shrubs, fallen pine needles, grasses and dead trees. Prescribed burns tend to happen in the winter, spring and fall when the weather is cooler and wetter to keep the planned fires under control. Forest managers have used prescribed fires for some time now to reduce wildfire risks, but the practice grew out of favor as policymakers expressed concern about air quality and held to the flawed belief that all forest fires were bad.

Researchers say that prescribed burns release fewer particulate matter or smoke in large part because they cause less damage and are much easier to control than unexpected blazes, the report said.

According to the study:

Destructive wildfires have higher rates of biomass consumption and have greater potential to expose more people to smoke than prescribed fires. Naturally ignited fires that are allowed to self-regulate can provide the best scenario for ecosystem health and long-term air quality. Generally, prescribed fire smoke is much more localized, and the smoke plumes tend to stay within the canopy, which absorbs some of the pollutants, reducing smoke exposure.

The researchers’ conclusion underscores that the rational, science-based approaches that the Washington Forest Protection Association has long advocated for and its members have practiced for years not only help ensure healthy, resilient forests, but they also help prevent harmful health effects of wildfire smoke.

Applying proven-effective strategies like tree thinning, prescribed burns, installing fuel breaks and addressing threats from insects and invasive species to actively manage their lands, Washington’s private forestland owners are demonstrating that sound forest management practices are good for the environment and help protect public health while safeguarding their growing forests. Preventing major wildfires also can save money and help protect wildlife and water quality. Not to mention, trees and branches removed during thinning can be used for timber products like paper, particle board and cross-laminated timber.

In recent summers, wildfire smoke has blanketed skies in the Pacific Northwest, impacting air quality and causing health concerns in both eastern and western Washington. State climatologists predict a hot, dry summer this year with areas west of the Cascades facing particularly high wildfire risks. The Department of Natural Resources reported that the month of March had 51 fires, with 49 of them occurring west of the Cascades in Lewis and Cowlitz counties.