The trees residents see immediately after a prescribed burn may look like they are dead. However, native species such as Ponderosa Pines are adapted to survive low-intensity fires that are generated by prescribed burning. The trees will return to their happy green state typically within one year. Prescribed burning cleans up the brush and low hanging limbs that can stress large Ponderosa Pines.
For millennia, our region was shaped by fire, and our mid- and lower elevation forests (think forests of pure or mostly ponderosa pine around Sisters, Bend, and Sunriver) were maintained by frequent, light, low-intensity fires, generally every five or ten years. Controlled burns are carefully planned and implemented only under prescribed conditions. These conditions are selected to carry most of the smoke out of the communities and when the fire will do the best restorative work on the ground.
Want to learn more? Check out Dr. Paul Hessburg’s Ted Talk on living with wildfires. Watch the TED Talk
The intent of prescribed burning is to reduce the amount of vegetation on the forest floor. This will make local forests healthier and reduce the severity of wildfires in the summer months. Implementing prescribed burns near homes, town, and the built environment creates a resilient forest where firefighters can be more effective in suppressing the fire.
Fire was here before us. For millennia, our region was shaped and maintained by fire. Having fire present is essential for stimulating fire-dependent trees and plants, maintaining wildlife habitat for certain species, cycling nutrients and sustaining important functions of the forest ecosystem. Our forest needs fire to maintain their health. We share our communities’ concerns regarding health, visibility, and livability related to smoke produced by controlled burns. But controlled burns, which are primarily conducted in spring and fall, are a critical step in forest restoration. Research shows that in addition to sustaining important forest ecosystem functions, they significantly reduce the likelihood of out-of-control fires, the kind that means danger for our communities and hazardous air for weeks at a time.
It is important to know a great deal of work happens in the forest before a prescribed burn is conducted, including thinning out and removing small trees and brush. Completing these steps reduces the amount of material to burn, which in turn reduces the intensity of the fire and helps ensure that prescribed fire produces less smoke, achieves forest restoration goals, and can be safely controlled. For more information on what goes into planning and preparation for a prescribed burn check out Minimizing Smoke Impacts.
The particulate matter (also called “PM”) in wildfire smoke poses the biggest risk to the public’s health. The potential health effects vary based on the type of plants burning, atmospheric conditions and, most importantly, the size of the particles. Particles larger than 10 micrometers usually irritate only the eyes, nose and throat. Fine particles 2.5 micrometers or smaller (PM2.5) can be inhaled into the deepest part of the lungs and may cause a greater health concern.
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Each type of respirator can come in several varieties, each with its own set of cautions, limitations, and restrictions of use. Some respirators require testing to ensure a tight fit to the face, and should not be used with facial hair or for children. For more information on the different types of respirators and their limitations and uses visit Respirator Fact Sheet from the CDC.
Portable air cleaners with HEPA filters and/or electrostatic precipitators (ESP) can reduce indoor particle levels, but most are not effective at removing gases and odors. Air cleaners using ozone will not remove particles unless they also use HEPA filters and/or ESP technology. Also, humidifiers or dehumidifiers are not air cleaners and will not do much to reduce the amount of particles in the air during a smoke event.
You can reduce smoke exposure by keeping the windows closed and using the air conditioner on the recirculate setting. This can reduce exposure to particles, but not to the toxic gases in wildfire smoke.