A Cronkite News Service Weekend Special

INVASIVE GRASS THREATENS HOMES, PEOPLE AS WELL AS NATIVE PLANTS

NOTE: Aaryn Olsson is cq in 9th paragraph.

Photos: 1 | 2 | 3 (thumbnails, captions below)

By JONATHAN J. COOPER
Cronkite News Service

PHOENIX _ Buffelgrass has become so entrenched in southern Arizona and is spreading north so rapidly that some experts are now talking less about eradication and more about protecting homes and people from the intensely hot fires it can sustain.

“This is an urban and suburban threat to life and property,” said Travis Bean, a principal research specialist at the University of Arizona Desert Laboratory in Tucson. “We need to first go in and make sure that where we live is safe, and that we’re not going to start losing people to buffelgrass fires.”

The invasive species, which is native to the African savanna, grows and spreads quickly, turning vast swaths of desert into tinderboxes where wildfires spawn flames 20 feet high.

Planted around Tucson in the 1930s as cattle forage and for erosion control, it has reached the desert around Phoenix, the Valley’s urban parks and the national forest nearby.

Experts have long seen buffelgrass as a threat to native plants because areas thick with it burn at temperatures reaching 1,200 degrees, which is hot enough to melt a soft drink can. After such a fire, the thing most likely to grow back is buffelgrass.

But what makes it so dangerous to desert life also makes it a threat to developed areas where buffelgrass flourishes. That’s already the case around Tucson, especially in the foothills of the Santa Catalina Mountains on the area’s north side.

“What happened in California this year, we’re getting closer and closer to that here in southern Arizona,” Bean said.

Where buffelgrass has gotten out of control, experts say clearing buffer zones may keep fires away from homes and limit their size.

Bean and other researchers also fear an environmental catastrophe from buffelgrass if colonized areas grow together and create the potential for a fire that could wipe out vast swaths of desert plants.

“That scenario may not be that far away in the Catalinas,” said Aaryn Olsson, a senior research specialist with the UA’s Arizona Remote Sensing Center.

Such a fire would kill cactuses, palo verdes and other native plants, which are not adapted to survive large fires and might never grow back.

“There goes the saguaros, the palo verdes, the wildflowers,” Bean said. “You end up with species that can survive a 1,200-degree fire, which is pretty much just buffelgrass.”

Even without a fire, buffelgrass can change the ecosystem by crowding out seedlings from native plants, Bean said.

Ripping out buffelgrass by hand is usually the only sure way to get rid of it, Bean said. Herbicides only work during the early monsoon season when the grass is green and growing.

Buffelgrass didn’t spread noticeably until the 1990s. Now it’s moving quickly into new areas. It spreads in the wilderness and near roadways, where cars can spread seeds long distances.

The plant can survive throughout most of Arizona south of the Mogollon Rim, experts say. Even parts of southern Mohave County and areas as far east as Safford are suitable for buffelgrass, although it is unlikely to reach those areas, Olsson said.

When buffelgrass reaches a new area, only quick action can stop it.

“If you find it in Safford, you can go out and get it and you can eliminate the population at this point,” Olsson said. “If it gets in there and you don’t see it for a few years, it’s going to be a lot more difficult.”

In Phoenix, volunteer groups are attacking vast buffelgrass patches that have infested Piestewa Peak.

“The whole mountains are covered with it there,” said Claudia Bloom, who started the Phoenix Weedwackers group and organizes a monthly cleanup with about 20 volunteers. “It was desperate.”

The group has focused on clearing buffelgrass from trailheads, where cars and cigarettes make the risk of fire particularly severe.

The plant has also spread into the Tonto National Forest north and east of Phoenix, where officials have been alarmed by its rapid spread.

“It’s a scary weed,” said Patti Fenner, a noxious weed program manager for the Tonto National Forest.

Fenner said a project to widen the U.S. 60 between Superior and Florence Junction was the first in the country to include a contract provision requiring a contractor to take steps to prevent spreading invasive plants such as buffelgrass.

Officials have sprayed roadsides and enlisted convict labor to rip out weeds, but Fenner said she’s frustrated by the slow progress.

“We’re doing what we can, and we’re trying real hard, but I think we’re losing the big battle,” Fenner said.

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PHOTOS: Click thumbnails to see full-resolution images and download

CAPTION FOR BC-CNS-BUFFELGRASS THREAT: Buffelgrass blankets an area of the Santa Catalina Mountains near Tucson. The invasive plant species is so established in southern Arizona and is spreading north so rapidly that scientists are now talking less about eradication and more about protecting homes and people from the intensely hot fires it can support. (Credit: Aaryn Olsson, University of Arizona, via Cronkite News Service)

CAPTION FOR BC-CNS-BUFFELGRASS THREAT: Buffelgrass blankets an area of the Santa Catalina Mountains near Tucson. The invasive plant species is so established in southern Arizona and is spreading north so rapidly that scientists are now talking less about eradication and more about protecting homes and people from the intensely hot fires it can support. (Credit: Aaryn Olsson, University of Arizona, via Cronkite News Service)

CAPTION FOR BC-CNS-BUFFELGRASS THREAT: Buffelgrass blankets an area of the Santa Catalina Mountains near Tucson. The invasive plant species is so established in southern Arizona and is spreading north so rapidly that scientists are now talking less about eradication and more about protecting homes and people from the intensely hot fires it can support. (Credit: Aaryn Olsson, University of Arizona, via Cronkite News Service)