National Fire Plan Success Story
Invasive Grass Fuels Treatment in WUI
Saguaro National Park, Arizona
National Fire Plan - Fuels Reduction
2009
The invasive weed, buffelgrass (Pennisetum ciliare), has vigorously expanded in the Sonoran Desert over the past two decades. Buffelgrass has unprecedented fuel loads of up to 4 tons/acre in Saguaro National Park. Saguaro National Park was established in 1933, and since that time, urban growth has expanded up to the park boundary. Wildfires in buffelgrass threaten not only the park’s signature plant, the saguaro cactus, and the entire Sonoran Desert ecosystem, but also the lives and property of area residents.
Data collected in the park suggest that herbicide application is an effective tool in preventing the spread of buffelgrass and in decreasing fire threat in sites that are already dominated by buffelgrass, reducing the fuel load by one third in 1.5 years and two thirds in 3.5 years. However, herbicide control must be done when at least fifty percent of the grass’s leaves are green.
In 2009, the park hired a crew of three Student Conservation Association interns to treat buffelgrass along all roads within or bordering the Tucson Mountain District of the park. Most roads were sprayed by the beginning of August, but a lack of sustained precipitation caused mature plants to become dormant and prevented seed germination. Herbicide application was suspended and hand removal was conducted until late rains caused more green-up and a small germination event. During the project, a total of 69 acres of buffelgrass were treated (14 acres of manual removal and 55 acres of herbicide control).
According to park superintendent Darla Sidles, “the project was a success because of the collaboration of the employees from all divisions within the park.” The most challenging component of the project was working along a busy, winding road with no shoulder. A safety plan and traffic control plan were implemented in close coordination with law enforcement rangers and an independent contractor. Approximately two tons of buffelgrass were removed manually along this three-mile stretch of road.
Contact: Perry Grissom, Fire Ecologist, (520) 733-5134.