Sources of Pollution
Prescribed fire
There are two “categories” of prescribed fire. The first category relates to the burning of piled biomass. In this case, the excess woody biomass is cut from the forest and piled. The piles are left to dry for up to several years, then the piles are burned as a means to dispose of the excess biomass. There is no ecological benefit to this type of fire, therefore it is desirable to find other non-burning ways to remove this excess biomass when possible.
The second category is called “understory” or “broadcast” burning. This type of fire is generally performed once the excess biomass has been removed; the fire is managed to burn across the entire landscape at a low intensity (staying pretty close to the ground), mimicking the historical natural fire regimes that our forests relied on to stay healthy. This type of fire provides significant ecological benefit, and is necessary to truly restore our forests as well as reduce the occurrence of the excess biomass that increases fire severity. Because this type of fire provides significant ecological benefit, as well as reduced fire risk, it is desirable that burn days are used for these types of burns instead of pile burns. Currently, for a variety of reasons, more pile burns are performed than understory burns.
For more information on prescribed fire visit our fire science page.
How does smoke management relate to prescribed fire?
The smoke generated by prescribed fire is generally far less than that generated by the large, catastrophic wildfires that prescribed fires help prevent. However, prescribed fires, which occur far more regularly than catastrophic wildfires, must not generate smoke that will cause a violation of air quality standards, which are based on protecting humans from the negative health impacts of smoke. Therefore, smoke management is a key component in planning prescribed fire projects. Each year, there are a limited number of “burn days” available for burners to perform prescribed fire. Burn days are determined by state and county agencies, depending on the area, that use meteorological monitoring equipment and models to predict weather conditions. When a prescribed fire project is planned ahead of time, that plan will dictate what the weather conditions must be in order to conduct the burn. The required weather conditions are based on minimizing the smoke impacts from the prescribed fire. For example, burns are often allowed when conditions will cause the smoke from a fire to move vertically such that it moves up and out of an area, thus creating very little impact to nearby communities.
Real time smoke monitoring in the Sierra Nevada... Click here.