A Plant That’s Everywhere Is Fueling a Growing Risk of Wildfire Disaster
There is a plant that quietly exists in every corner of the United States, and is unfortunately contributing to the growing fire-emergency wildfire grasses. That inconspicuous plant is grass, a plant that every American is most familiar with, and is also believed to be a fire hazard because of its set.
It may come as a surprise, but grasses can be found almost anywhere. Whether in fields, lining the streets, or even on peoples’ lawns. Under specific conditions, grasses can act as a natural speed booster and a small spark in the middle of a grassy field has the potential to spring forth a fire that travels a lot quicker than the infernos seen in forests. Due to its convenience and availability, grass can successfully be classified as a wildfire-suppressing tool.
The Role of Grass in Wildfire Spread
“Any environment you can think of, there’s a type of grass able to survive in it,” elaborated Adam Mahood, a research ecologist with the U.S. Department of Agriculture’s Research Service. “You’re bound to find grass in any 10 foot area that isn’t paved.”
Grass fires and forest fires are different in many ways. While forest fires may be more intense and higher in heat, grass fires are much faster. Under the right wind conditions, a grass fire can outpace firefighting crews, putting homes, infrastructure, and ecosystems at risk.
The decades from 1980-2010 showcased rising numbers of homes destroyed by wildfire, more than doubling from 20,000 homes to 40,000. The cause of wildfire home destruction may be attributed to grass and shrub fires, especially in the western region. Studies have shown that two-thirds of homes fell to fire in areas dominated by grass and shrublands, with 80% of these consumed in grass and shrub fires.
The Wildland-Urban Interface and Escalating Risks
One of the most influential reasons that cause this danger is human development in areas that are prone to fires called the Wildland-Urban Interface (WUI). As suburban development creeps towards grasslands and other fires prone areas, more people are habitating at the edge of natural ecosystems. This presents a dual risk:
- Increased risk of ignition: Most wildfires are human induced, be it through machinery, campfires, or accidental sparks.
Currently, around 44 million households in the United States reside in the WUI which is a 46% increase in the past 30 years. This coincides with the increase in the activity of wildfires creating a disturbing feedback loop which exposes more households to wildfires that are raging at an increased speed.
“Property owners need to do their part too,” remarked Bill King, a U.S. Forest Service officer overseeing portions of Kansas and Colorado. “These fires get so big, intense, and sometimes wind driven that they could spot miles ahead even if we have a huge fuel break.”
Climate Change and the Perfect Firestorm
Moreover, the fires that are grass-fueled are aggravated by climate change. The increased temperatures, changing patterns of rainfall, and increase in the frequency of drought are creating the perfect atmosphere to spread wildfires.
“It’s a little bit like Goldilocks. Not too wet, not too dry, just right, with plenty of ignition” explains John Abatzoglou, a climate professor at the University of California, Merced. He adds, “Globally, the places that burn the most are places that have intermediate precipitation.”
These changes are particularly evident in the northeastern region of the United States, the Great Plains, and other areas with continental climates. Winters are getting warmer, while snow cover is waning. Spring precipitation nourishes dense vegetation that emerges during the growing season. Toward the end of the winter and beginning of spring, the warmer winter and early spring temperatures dense vegetation dieback, while excess dead material accumulates to create highly combustible fuel beds.
Like shrubs, grasses can dry to a combustible state in a matter of hours. This “weaponized” drying, coupled with sparks, strong winds, and the presence of invasive shrub species create the perfect recipe for quick-fire spread. “These compound extremes, these sequences of extremes that follow one another…if you get the right sequence, it can be game on for this sort of wildfire,” Abatzoglou explains.
Grass in Forest Systems: An Extreme Fire Hazard
Grass has invaded forested regions. In this ecosystem, it serves as a fuse, connecting smaller, easier-to-ignite fuels to larger, drought-stressed trees. When trees undergo prolonged heat exposure or insect infestations, grasses take over, resulting in a highly flammable understory.
According to King, “While other plants struggle for months or longer to burn, grasses, on the other hand, can go through that process in a matter of months or even sooner.”
A substitution of native and nonnative grasses for forests directly heightens the risk of fires. Fire-prone grasses and the accelerated turnover of vegetation due to flammability defeat the ecosystem’s ability to recover, and in turn, repeat the cycle of devastation.
Grass in Fire-prone Desert Ecosystems
Annual grasses are the main culprit transforming fire dynamics in desert ecosystems. These grasses can create a dense carpet of fuel on the desert floor. When it’s hot and dry, these grasses easily catch fire, creating burning fuel in places that didn’t previously have fire.
The recent fires within California’s Mojave National Preserve are a perfect example of a trend we’ve been tracking. Invasive red brome grass not only increases the risk of fires, but also fueled the recent fires within Mojave national park. Due to invasive red brome grass, we’ve lost over a million Joshua trees. invasive red brome grass increases the chances of fires as it hinders the rate at which the native vegetation can recover.
“The desert fires we’re seeing now are much more extensive than those in previous decades,” said Mahood.
The Role of Drought and Weather Extremes
Combined droughts and extreme temperatures have the potential to increase the risk of fire in a certain area. Out in the West, fires are becoming more and more prevalent due to winds and extreme droughts. The combination of dry, rainy springs, followed by blistering summer dry spells can create a recipe for explosive grass growth.
This also serves as a great explanation for why we have begun to see the emergence of mega fires, like the Smokehouse Creek Fire in Texas and the Marshall Fire in Colorado which, as we all know, resulted in the destruction of over 1000 homes in 2021.
“Fire seasons were much milder two decades ago compared to what we have to deal with now and we are already facing the brunt of it,” said Mahood.
Fire Hotspots and Invasive Species
Invasive grass species pose a great deal of problems. Unlike native species that might have co-evolved with the climate and fire regime of the region, invasive grasses, for example;
- Grow thick and provide constant fuel and coverage for fires
- Recover quickly after experiencing burns
- Outcompete native vegetation, further changing the dynamics of vegetation fires
Invasive species, such as cheatgrass and red brome, are notorious for the increased frequency of fires in the western parts of the state, including California. These grasses provide fire with a continual fuel supply and enable fire to spread quickly and overcome areas that were once fire resistant.
The Wildfire Problem
Fires are commonly started by accidents, such as operating vehicles, using equipment, or simply having a campfire. This, combined with the construction of buildings in high-risk areas, creates a growing threat for wildfires.
The construction of houses in the WUI results in increased chances of an accidental fire, but it is the limited resources for fire control that pose a large problem. Alongside these limited resources, firefighters are forced to deal with fast-moving grass fires that race past containment lines, making fires incredibly difficult to manage.
Fires have proactive measures as well, such as the WUI and fuel breaks. These were specified as the defensible space and local fire law. These measures lay out what needs to be done by the homeowner to live in a productive and safe environment.
The Feedback Loop of Grass and Fire
The feedback loop of grass and fire illustrates the self-reinforcing relationship between the two. Fire clears areas for the grass to regrow, and grass, being quick to recover, then flammable, becomes the fuel that ignites the following fire. With time, this process can profoundly alter the landscape and replace the slower-growing forests or native vegetation with rapidly burning grass.
Take the sagebrush ecosystem, for example, or the fire and fuel feedback loop. Over the last two decades, half of the sagebrush lands in the lower 48 states have either been lost or degraded, largely due to the invasion of fire-fueling grasses that inhibit the recovery of native vegetation.
Mahood warned that the current situation might look extreme, but what seems extreme now could very well pale in comparison with what the next decade has in store.
Preparing for Grass-Fueled Wildfires
Communities that are geographically more vulnerable to grass-fueled fires need to consider the following mitigative approaches.
- Vegetative Management: Removal of flammable grasses, creation of firebreaks and defensible spaces around homesteads and invasive species.
- Construction: Non-combustible fireproof materials used for roofs, and ember-resistant vents to fireproof spaces and roofs.
- Fire Detection: Real time detection and monitoring for fires that could pose danger to residents.
- Design: Controlled development in fire-susceptible areas and avoidance of expansion into the WUI zones.
- Climate Adaptation Strategies: Being aware that fire danger will increase due to warmer temperatures and less rainfall, and planning for it.
Public awareness is just as important. Residents in fire-prone areas need to know how to avert accidental ignitions as well as how to mitigate the escalation of grass fires.
The Future of Grass Fires in a Warming World
The danger of grass-fueled fires will only increase as climate change exacerbates heat and modifies rainfall patterns. Grass is a widespread and versatile plant that can rapidly recover from fire damage, guaranteeing its continuous availability as fuel.
Without concerted efforts, experts predict that wildfire seasons will be extended, becoming more severe and destructive, particularly in the western United States and the Plains. The compounded effects of climate change, uncontrolled human activity, invasive plant species, and reckless wildfire management welcome a new wildfire catastrophe. Grass is the fuel of choice.
Mahood concludes: “It may seem bad now, but this will probably not seem nearly as bad in the next decade. Remember how fire seasons used to be just two decades ago? now, that seemingly nothing.”
Key Takeaways
- Grass is a common and ignitable fuel that fosters the rate of fire spread, particularly in the Plains and western U.S.
- Grass fires are capable of moving more quickly than forest fires making them more dangerous and giving firefighters less time to respond to the threat.
- The increase of construction and human activity in the wildland-urban interface significantly increases the chances of a fire starting and the cost of damage to the property.
- Changes in climate has risked fire outbreaks by making Winters more mild, Summers hotter, and having unpredictable rainfall.
- Invasive species of grass not only increase the chances of fire, but also maintain the intensity of said fires by providing a constant source of fuel.
- Communities must adopt fire-resistant construction and early-warning systems.
- The self-sustaining cycle of fire and grassland revitalization guarantees that unless action is taken, the world’s fire-prone areas will continue to expand.
We continue to see grass take over shrubs, deserts, and forests, providing the world with a new source of wildfire risk. Facing this new reality is important in the era of climate change extremes. For more on climate impacts, visit The Climate Post.
