As wood burns, many chemicals such as carbon dioxide, carbon monoxide, methane, nitrous oxide, and ozone are released. For people with respiratory health issues, the biggest concern with smoke is particles 2.5 microns or smaller (approximately 1/30th the diameter of a human hair), commonly called PM 2.5. These particles, when inhaled, can travel deep into the lungs, clogging the alveoli where oxygen is absorbed into the circulatory system.
By Mark Buckbee, Educational Director, Communities for Healthy Forests
Most of the forests of the western United State have evolved in an environment of periodic fire initiated
by Native Americans or lightning. Some forests such as Pacific coast spruce/hemlock forests burn very
infrequently, with multi-century return cycles, while other forests such as central and eastern Oregon
Ponderosa Pine forests experience fire return cycles measured in decades. Efforts to bring “good” fire
back into our forests and make them more fire resistant and resilient will necessarily create smoke.
Most wildfires and nearly all high severity wildfires occur during the summer and early fall. As summer
progresses, fuels continue to dry out. By the time fall rains arrive, even large downed logs have low
moisture content, and can burn. Dry season wildfires result in multiple negative outcomes: large logs
which are good for soils and wildlife are consumed; fires burn hotter with longer flame length and are
harder to control; prolonged hotter surface fires damage soil; and the resulting dense smoke can last for
weeks, reaching far into the atmosphere and carried in the winds. As wood burns, many chemicals such
as carbon dioxide, carbon monoxide, methane, nitrous oxide, and ozone are released. For people with
respiratory health issues, the biggest concern with smoke is particles 2.5 microns or smaller
(approximately 1/30th the diameter of a human hair), commonly called PM 2.5. These particles, when
inhaled, can travel deep into the lungs, clogging the alveoli where oxygen is absorbed into the
Smoke can also have economic impacts. Long term exposure to smoke by ripening grapes has shown to
reduce their value. The tourism industry is frequently affected when long term smoke inundates
destinations, resulting in canceled travel plans. Even airports have canceled flights during dense smoke
inundations. Then there is the issue of livability; no one wants to live in smoke for extended periods. To
reduce these harmful impacts, forest managers want to apply prescribed fire during favorable,
controllable burning conditions.
Millions of acres of federal land in Oregon need treatment to reduce fuel loads. Treatment can include
mechanical methods such as thinning, masticating, and mowing and prescribed fire. If we are to catch
up on this backlog, we must be able to use appropriate tools.
Ramping up prescribed burning presents many challenges. First, younger stands and certain species with
thin bark such as Douglas Fir and true firs can be damaged by fire. Also, prescribed burning is not
appropriate in stands with heavy fuel loads.
Another challenge is the inevitable smoke. When weather and fuels conditions are optimal, prescribed
burning produces much less smoke than wildfire, particularly when fuel loads have been mechanically
reduced in advance.
To protect people from the deleterious effects of smoke, the Oregon Department of Environmental
Quality, Oregon Health Authority, and Oregon Dept of Forestry developed rules to manage prescribed
fire smoke. The rules prohibit burning if smoke is likely to drift into “Air Quality Areas” which consist of
cities, densely populated areas, national parks, Wilderness, and other special management areas. It also
places limitations on the amount and duration of smoke that can be released. If forest managers cannot
expand and accelerate fuel reduction projects, these federal forests will continue to burn in wildfires.
What actions should be taken to allow managers to get their work done? Legal and regulatory
impediments to project development and implementation on Federal and lands must be reduced.
Expansion of existing and development of new markets for wood fiber to utilize rather than burn smaller
materials must be supported. Our air quality regulators must have a robust alert system to inform
sensitive groups that smoke intrusions are possible, offer safe havens for people whose homes or
worksites do not mitigate smoke and tolerate the currently banned smoke intrusions to permit more
prescribe burning. Through workforce development we must train and increase the skilled practitioners
needed to implement prescribed burning projects. Federal agencies must allocate more resources to
planning and implementation of fuels treatment projects. And finally, the EPA and DEQ must modify the
restrictions on planned smoke emissions from prescribed burning if we are to have any impact on
reducing the unregulated smoke emissions resulting from the uncharacteristic wildfires which we have
Mark Buckbee is a retired Federal forester who had a 34-year career with the Bureau of Land
Management in western Oregon. He holds a Bachelors degree in Forest Resources Management from
SUNY-Syracuse and a Masters degree in Forest Science from Utah State University.