Buffelgrass, the intensely flammable plant that has invaded and colonized the Sonoran Desert, is the suspected culprit in a lot of brush fires in the Tucson area and is now the subject of a study that seeks to demonstrate the severity of the problem.
The Tucson Fire Department is the source for the first "Integrated Brushfire Database" put together by the Southern Arizona Buffelgrass Coordination Center.
It shows that brush fires can occur any day of the year, but they peak in May and June, falling off precipitously when the rains arrive in July.
No area of the city is immune, but the area's dry washes account for a lot of the fires - 7,070 of the 15,825 documented between January 2000 and July 2012. Most occur between 2 and 9 p.m. with the peak at 5 p.m., the study shows.
Neal Kittelson, the invasive species project manager at the center, began with a mapping study that, while it doesn't convict buffelgrass of its suspected major role in carrying urban fire, identifies a lot of fire locations where it is known to exist and where it may pop up.
Buffelgrass can easily out-compete native grasses after a clearing fire. "Even if it's not the culprit, there is a good chance that buffelgrass invades after a fire," said Kittelson.
Buffelgrass fires burn fiercely, he said. "We just recently had a demonstration burn and buffelgrass fires definitely have longer flame lengths. They are hotter, an average 1,200 degrees (Fahrenheit), and are hotter longer than normal grass fires - after 10 minutes still up to 600 degrees. They hold a lot of biomass, a lot of fuel."
Kittelson intends to expand the database into an annual report covering all of the region's fire districts.
Eventually, he'd like fire districts to identify the types of grasses burning, but that is not now a part of the software programs used to report fires.
Anecdotally, local fire officials know buffelgrass is a problem. "We have a lot of experience with it," said Tracy Koslowski, fire marshal for the Drexel Heights Fire District.
"It burns real hot, and it does spread once it gets going, and it's really difficult to put out."
Drexel Heights, which serves 60 square miles of developing suburbia west of Tucson, has a lot of buffelgrass, said Koslowski. "The buffelgrass seems to like to grow right along the roadway. I'm looking at it now right outside my window across the street."
Like Drexel Heights, Tucson Fire Department does not classify the vegetation type when it puts out brush fires, but knows it is a problem. "It flashes very fast. It can spread fire from one location to another very quickly, and it burns very hot," said Assistant Chief Joe Gulotta.
Gulotta said it is especially dangerous when it grows next to homeowners' wooden fences, where a carelessly thrown match can start a fire that eventually burns a home.
The colonization of area washes is a particular problem, said Koslowski.
"We don't have an easy means for us to access with no roads. There are no hydrants, so bringing water in is tough. We take little brush trucks in off-road, and they don't carry as much water," she said.
Lindy Brigham, the buffelgrass center's executive director, said one of her organization's goals is spreading the word. Buffelgrass is a potential danger, she said, "but it has to have an ignition source."
People need to keep that in mind when discarding cigarettes along roadways, and school-age children need to know about the significant fires that can be caused.
Brigham said it may not be coincidence that fires peak during after-school hours.
Koslowski said, "We don't want to say all our summer brush fires are caused by kids, but many are." The other big cause is motorists' discarding lit cigarettes, she said, as evidenced by many fires starting along Ajo Highway, which runs through the district.
"The buffelgrass seems to like to grow right along the roadway. I'm looking at it now right outside my window across the street."
fire marshal for the Drexel Heights Fire District
Information on buffelgrass and how to control it: www.buffelgrass.org
Reporter Tom Beal can be reached at firstname.lastname@example.org or 573-4158.