Wildfires in Arizona are getting worse due to invasive species, new study says
Wildfires in Arizona are burning hotter, faster and more often, in part due to a selection of invasive plant species taking over the desert environment, according to a report by nature experts.
The study published in May described a grass-fire cycle that has caused sparse desert landscapes to turn into sprawling grassland that fills the gaps between native plants and initiating dry tinder made ready by the hot Arizona sun.
The study was published by the Southwest Fire Science Consortium with funding from the Arizona Wildfire Initiative.
The study highlighted the rapid and uncontrollable transformation of the Sonoran Desert, citing the 2005 Cave Creek Fire, which burned over 250,000 acres, and three fires in 2020 that collectively scorched nearly 400,000 acres.
All of those fires were primarily fueled by those invasive plants, especially red brome, which the study said grew in correlation between winter precipitation and fire number and size.
The study cited a "self-perpetuating grass-fire cycle that progressively excludes native plants," causing the Sonoran Desert to steadily be taken over by the invasive plants that create the fuel for wildfires.
Eight core invasive plant species were identified in the study, mainly winter and perennial grasses such as fountain grass and cheat grass, known for their ability to overtake the environment.
The study predicted that this change in the Sonoran Desert would continue to allow wildfires to now travel down and up the mountains that held forested woodlands that were typically the source of wildfires.
"Formerly, wildfires in semi-desert native grassland, woodlands, and forests at higher elevations have invariably died out as they moved downslope and encountered the more open desert scrub," read the study.
The study cited the 2020 Bush Fire and 2021 Telegraph Fire, both of which started in desert lowlands with the help of invasive plants in the regions, expanding to forested environments and burning nearly 200,000 acres of land in the Tonto National Forest.
The study said one of the ways to combat growing wildfires was to launch campaigns to stop the invasive plants before they reach a problematic size.
This is implemented via state foresters issuing prescribed burns, and even using livestock cattle to graze on an area riddled with invasive plants waiting to act as fuel.
The study said land managers need to establish more fuel breaks in the land to stop fire progression, use established criteria to triage wildfires and restore environments to their native state without the invasive plants.
Needed assistance: New firefighters, equipment now available to combat Arizona wildfires
Further research was needed to make fire response more efficient, helping state foresters battle fire-prone landscapes and develop shared efforts to respond to them.
This article originally appeared on Arizona Republic: Invasive plants are making Arizona wildfires worse. Here's how
