Wildfire
Wildfire is the uncontrollable spread of fire through a large area. It typically occurs when small fires spread from the forest floor into the crowns of large trees via "ladder fuels" and are spread by wind driven embers.
Three factors contribute to wildfire. Ladder fuels, air temperature and moisture
Our forests have been damaged. First by being clear cut and then by suppression of small naturally occurring fires which normally clear out ladder fuels without developing into wildfire.
Burning the Forest to Save It?
Currently there is a large effort to eliminate ladder fuels by manual thinning. When the ladder fuels are thinned, you end up with a lot of wood debris. What to do with this?
Currently, these fuels are piled and burned in place or trucked to a landfill or incinerator. Burning is the least desirable way to deal with these fuels. Proposed incinerator facilities at the Truckee Landfill and at Northstar will impact all of us with pollutants.
There is absolutely no evidence that burning biomass on the forest floor has any beneficial effect. All of the effects of this burning are damaging to human health and the environment. Most significantly, burning of the forest floor does not reduce the potential for wildfire. Biomass left on the forest floor improves forest health by improving moisture retention, nutrients, and reducing forest temperature.
The current policy is to burn this biomass. This recalls the Vietnam era slogan "We had to burn the village to save it."
CO2 Air Pollution
Burning releases the CO2 that the plants have captured from the atmosphere and stored in wood. This CO2 contributes to global warming and climate change. It is irresponsible to burn biomass which contains valuable stored carbon.
NOx, CO, O3 Air Pollution
In addition, burning creates new toxic molecules such as NOx, CO and ozone which can move deep into lungs causing cancer and other lung diseases.
Particulate Air Pollution
Wood smoke creates particulates which can enter the lungs and cause asthma, lung disease and cancer.
VOC Air Pollution
Wood smoke also creates chemicals called volatile organic compounds (VOC) which can also cause lung disease, heart disease and cancer. These compounds are not removed by air filters and settle on surfaces in homes where they are slowly released into the air. The only way to remove these is to clean all surfaces.
Burning Stuff is Bad for your Health and the Environment
These pollutants are created by wildfires and also by controlled burns. Even short term exposure to these pollutants can cause lung and heart disease and trigger cancer.
(A loophole in the Clean Air Act means that fire smoke air pollution is not tracked or reported when you see the "air quality" index for your area.)
Is there an alternative to controlled burns?
Why not just leave the biomass on the forest floor where it is no longer a ladder fuel for wildfire?
It is much preferable to mulch the wood in place and leave it on the forest floor. This mulch improves soil health by retaining moisture and reducing the forest floor temperature. Both of these things reduce the likelihood of wildfire. You don't have to transport the biomass, just spread it on the forest floor. Mulch on the forest floor does not contribute to wildfire. It is cheaper and easier to just leave the mulch from forest thinning in place on the forest floor than to burn it or transport it for burning or landfill.
Larger logs may have commercial value and can be sold as lumber products. Smaller longs can be left on the forest floor where they slowly decompose and are not a threat for wildfire.
Stop Burning Stuff
Humans have been burning stuff since they discovered fire. When the global population was low, forests and grasslands could easily replace the burned biomass. However, as the population increased and industrial farming cleared millions of acres, CO2 started to rise. The shift to fossil fuels further accelerated air pollution until the situation we find ourselves in today which is the current climate catastrophe of widespread air pollution and climate disruption.
We need to stop burning stuff. In the case of "controlled burning" of our forests we have a better alternative. Leave the biomass on the ground where it will improve forest health and reduce the likelihood of wildfire.
I would expect that the air quality districts would require solid scientific research to support the destructive burning. Both the damage to human health and the environment are substantial. In order to justify this burning, there must be some overwhelming compensation to human health and forest health. I have found no evidence of any benefit to human health or forest health.
Q & A
Don't some trees rely on fire to spread their seeds?
Yes, they do. However, when you've just spent a lot of effort to thin the forest, the last thing you need is to encourage is more new trees.
Are there other alternatives to open air burning?
Biochar
Another alternative is to make biochar which is wood heated in a closed kiln without oxygen. This creates pure carbon. Manufacturing biochar requires a specialized kiln and converts about half of the biomass into biochar. The remainder is released as CO2, particulates, and VOC. Depending on the design of the kiln, some of the VOC and particulates can be captured.
Biochar is mainly used for soil application and is known to improve soil nutrient availability, aeration in soil, and soil water filtration. Biochar is in demand by farmers as a soil amendment. Biochar locks up the carbon for literally centuries.
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