California Coast & Ocean

As I rode along Highway 78 with Hawkins, he pointed to the road's pastel-green shoulders. After burning, they had been sprayed with a mix of hydromulch and wildflower seeds. "That stuff's just for show," he said. "It won't do much to hold the soil, but at least it's native wildflowers."

After the Cedar Fire in October 2003, Burned Area Emergency Response teams broadcast 43,000 pounds of ryegrass seed across San Diego County. The purpose was to get some roots down quickly, to keep soil in place. But studies later showed that the ryegrass did not significantly reduce post-fire erosion. What it did do was to speed the conversion of scrublands to grasslands. Ryegrass helped spread a 1980 fire on Otay Mountain in San Diego County, which destroyed the chaparral stand there.

"If Californians lose native plants they lose native wildlife too," Hawkins said.

One large songbird, the coastal cactus wren, has been listed as a California species of special concern. It nests in prickly pear cacti, protected against predators by the sharp spines, and these cacti are being destroyed by the frequent chaparral wildfires. Ornithologists warn that the wren could disappear from Pacific slopes within a decade if frequent fires continue.

A Force of Nature
In fall the elements in southern California align to make the perfect firestorm. After months without rain, hot and dry Santa Ana winds blow west through the canyons toward the ocean. High pressure in the Great Basin pushes the winds toward a low-pressure area off the southern California coast. As the winds move from higher to lower elevations and squeeze through narrow canyons, compression heats and speeds them up, often to 50 miles per hour and faster. During October 2007's Witch Fire, locals in the San Pasqual Valley reported wind gusts of over 100 miles per hour. The fire jumped right over Interstate 15 as it blazed west.

Santa Ana winds send smoke from blazing scrublands out to the Pacific Ocean. Ash settles on the water, and eventually to the seafloor. Scott A. Mensing, a professor of geography at the University of Nevada, Reno, and two colleagues traced charcoal on the sea floor off the Santa Barbara coast to ash from burning scrublands. They carbon-dated it and, correlating their findings with other indicators such as pollen, reconstructed a 560-year record of Santa Ana fires. They found traces of at least 20 large fires in the Santa Barbara region during that period.

After researching charcoal records from the seafloor and the state's fire records, scientists have concluded that these large Santa Ana fires are a natural feature of the landscape.

No one knows how much chaparral and coastal sage scrub has been converted to grassland because of human-caused wildfires. The natural vegetation of California's coastal ranges is scrublands, yet as of 2004, Jon E. Keeley, research ecologist at the U.S. Geological Survey, stationed at Sequoia National Park, estimated that grasslands dominated by nonnative plants covered 25 percent of the coastal ranges. He is working with other ecologists to determine how many acres of scrubland were lost during the 20th century; they expect to have results in a couple of years.