Wildfires were five times more likely to be stopped by cropland than by grasslands, shrubs and forests, according to a new study led by the Reno-based Desert Research Institute.
But researchers also found that millions of acres of Western cropland have disappeared over the past four decades. And as states look for ways to conserve water, losing more farmland could come with an unexpected wildfire risk.
The study examined nearly 10,000 wildfires across 11 Western states between 1985 and 2024. Their findings were published in Environmental Research Letters.
Austen Lorenz, a Reno-based geographer who worked on the study, said several factors could explain why farmland appears to slow flames.
“Crops have a higher moisture in their tissue,” he said. “And they have a uniform, low stature, which can limit fire spread.”
Farmland can also give firefighters places to stage equipment and establish containment lines.
But not all crops offer the same protection. Lorenz said irrigated fields of alfalfa and hay, for example, tend to be less flammable because they contain more moisture. Harvested fields can also limit the vegetation available to burn, while orchards may help block flying embers.
The study didn't examine those differences, but Lorenz said researchers hope to explore that more in the future.
The study found roughly 10.6 million acres of cropland have been converted to other land uses in fire-affected watersheds over the past 40 years. About 80% became grasslands or shrubs, which can provide more fuel for wildfires. The remaining land was largely converted into housing and other development.
That's a concern as Western states look for ways to conserve water during drought, including taking agricultural land out of production.
Christine Albano, a DRI hydrologist and study co-author, said water conservation efforts should account for potential wildfire risks.
“We need coordination between agricultural programs and wildfire programs,” she said. “There needs to be more interaction to sort of jointly be addressing this.”
One possible solution is factoring farmland's wildfire-buffering benefits into agricultural conservation programs.
For Lorenz, the findings point to a bigger challenge as the West grows and its water supplies face increasing pressure.
“While we don't know the right answer, we do highlight that you need to think about both,” he said. “As we continue to build our cities — and have a need to feed people — we really have to have good foresight and planning of how we want to develop.”
This story was produced by the Mountain West News Bureau, a collaboration between Boise State Public Radio, Wyoming Public Media, Nevada Public Radio, KUNR in Nevada, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio and KJZZ in Arizona as well as NPR, with support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
