The new study featuring data from NASA’s ECOSTRESS mission has revealed the relationship between a wildfire’s intensity and the water in plants measured in the months before the fire.
The data didn’t just study how dry plants burn more than hydrated ones. It also looked into how some areas where vegetation had sufficient water burned more severely, possibly because fires had more fuel.
The research was led by scientists at NASA’s Jet Propulsion Laboratory in Southern California. Its goal is to study plant water-use data collected by ECOSTRESS, short for the ECOsystem and Spaceborne Thermal Radiometer Experiment on Space Station.
ECOSTRESS measures the temperature of plants as they heat up when they have no more water to consume. Researchers focused on data collected in 2019 and early 2020 over six areas: three in Southern California mountains and three in the Sierra Nevada. Later, these areas would become scorched by wildfires.
Other research has shown that wildfire season across the Western part of the US starts earlier every year and increases in length and intensity.
Researchers also studied California’s 33 million acres of forests. They looked into the relationship between wildfire and the availability of water to vegetation and how it could help fire-management officials identify how severe the damage will be if it ignites.
“We are in an intense megadrought – the worst in 1,200 years – and it’s creating conditions for more catastrophic fires,” said Christine Lee, a co-author at NASA’s Jet Propulsion Lab.
New NASA study could be a breakthrough for predicting wildfire severity and length
“Data sets like those from ECOSTRESS will be critical for advancing science and can provide information to support those who are responding to climate-change crises.”
Researchers found that the rate at which plants “sweat,” a process known as evapotranspiration, can help predict whether future wildfires are more or less severe.
“We were trying to understand what drives differences in why some areas have severe burns and other areas don’t,” said Madeleine Pascolini-Campbell, a water and ecosystems scientist at JPL. “The results show how crucial water stress is for predicting which areas burn the most and why it’s important to monitor vegetation in these regions.”
Like us, plants also struggle when it’s too hot outside. In addition, while sweating helps humans stay cool, plants also rely on evapotranspiration to regulate their core temperature.
Evapotranspiration combines how quickly plants lose water and how they release water through openings in their leaves, called stomates. Plants start closing their stomates to avoid losing too much of this crucial hydration.
“As a result, they start to heat up because they don’t have the benefit of ‘sweating’ anymore,” Lee said. “With ECOSTRESS, we can observe these really fine changes in temperature, which are used to understand changes in evapotranspiration and water-use efficiency.”