With several highly destructive wildfires happening in recent years, such as this year's Arctic wildfires and the 2018 California wildfires, scientists are now hard pressed to find new solutions that can prevent unintended damage from getting out of control. Aside from the significant damage it causes to the environment and wildlife, wildfire-struck areas also cost a lot to rehabilitate within the range of billions of USD.
Instead of focusing on reactive firefighting methods, scientists are exploring how preventive measures can be improved to stop these wildfires from beginning in the first place in areas of high risk. One such team of researchers from Stanford University was able to develop a gel-like material that exhibits promising properties for fire preventative applications. Details of this gel have recently appeared in the Proceedings of the National Academy of Sciences September 2019 issue.
Before working on this particular application, Eric Appel's research primarily focused on how hydrogels can act as carriers for pharmaceuticals. In a video for the Stanford Woods Institute for the Environment, he shares how the idea was born:
"My brother-in-law used to be the Fire Prevention Forester for the state of Hawaii. He asked me, 'Would it be possible to put fire retardants into these gels and use them to preventatively treat high-risk areas?"
"And immediately, the lightbulb went on."
The gel material is made from cellulose derivatives (basically plant material) and silica (a major constituent of sand), components which are essentially environmentally benign and nontoxic, so no adverse effects are expected when the material is put into action in these ecosystems. The material essentially acts as a carrier for fire retardants like ammonium polyphosphate and ammonium phosphate to increase their effectivity in use.
The combined action of both components also allows it to have good fluid properties so that it can be easily sprayed over vegetation. This is extremely important, as this allows a highly scalable method of spreading the material easily over large areas of land using airplanes or helicopters.
While conventional firefighting treatments make use of fire-retardant materials that are easily dislodged from vegetation, the carrier material has significantly stronger bonding to wildland plants, providing protection that can be used over extended periods of time. This was determined by conducting burn tests on treated grass and chamise (greasewood), two of the most common vegetation types in high-risk areas. Even after half an inch of rain, the formulations still performed quite effectively.
In addition, a mild resistance to biodegradation was also observed, which helps lengthen the service lifetimes of the materials even further so that they can be used over longer periods of time.
The only caveat observed by the researchers was that once the fires were burning for long enough, the flame-retardant properties of the gel diminished. After 420 seconds, they observed that the fires from the treated vegetation started to burn normally.
Nevertheless, the research provides a tool that, if applied widely enough, can provide much more protection to high-risk areas and prevent wildfires from even starting in the first place.
