Recently, the Los Angeles County Fire Department unveiled its new brush crusher. This machine, featuring a 14-foot-wide, 10-ton roller made of 1-inch steel plate, can crush hillside brush at the rate of 35 acres a day, even on steep slopes. Crews then control burn the compacted brush and grasses, creating up to 600-foot-wide fire breaks much faster than crews with chain saws can do it.
The crusher, which made its debut in Charmlee a few months ago, represents one of the latest approaches to clearing fire breaks in native areas of the western Santa Monica Mountains. Within the past year, the Fire Department has flattened a wide swath of native growth and animal habitat along the northwestern section of the park with the help of a large bulldozer which has flattened and scraped vegetation close to the ground. The result is about a 100-acre fire break, a very large percentage of Charmlee’s 540 acres. The Fire Department is planning more crushing inside the park’s boundaries.
The Fire Fighters are heroes in Malibu, and nobody questions their courage and devotion to saving lives and properties. But the latest addition of the crusher may signal a time to say, hey, let’s just hold on for a minute. We may have a legitimate disagreement here.
In a Los Angeles Times article on the crusher, state park Ranger Frank Padilla, Jr. was quoted as saying that burning the compacted brush generates less heat than standing brush and that the root burls are left untouched so that plants grow back readily. Biologist Jeff Smallwood of Cal State Northridge and a trustee of the Charmlee Nature Preserve Foundation, is inclined to disagree. In fact, Dr. Smallwood believes that the crushed brush heats up the ground more. As a result the heat overwhelms the evolutionary defenses built up by flora and fauna to natural fires.
Certain species in chaparral habitat are strongly adapted to relatively frequent fires, which have been suppressed by humans now for almost a hundred years, Dr. Smallwood says. The advantage to these frequent fires is that they move very quickly and they don’t get the earth very hot as long as fuel has not accumulated over several decades. Many plant species have a root crown-sprouting phenomenon where their roots survive cool, fast fires. They just put out a new crown. Also, insects, rodents and other animals can escape these types of fires by running away, or sometimes even walking away, or going underground to survive. Because these natural fires move quickly, he says, they are relatively cool, so they don’t sterilize the earth. But a glance at the Fire Department’s fire break in Charmleee indicates that something approaching sterilization is exactly what has happened. So far, the crown roots that insure the regeneration of native plants have not reappeared, even after many months. California Sagebrush (Artemisia californica; the principle component of an endangered habitat: Coastal Sage Scrub), Laurel Sumac (Malosma laurina), Scrub Oak (Quercus berberidifolia) and many other native chaparral species have not returned to locations where they have been crushed or bulldozed. Instead the area has been invaded by Black Mustard (Brassica nigra) and several non-native grasses and other weedy species. In Charmlee, the crusher has also pulverized a rock outcropping, a unique habitat for plants and animals, and damaged some small oak trees.
Marti Witter, Malibu’s city biologist, has passed along the concerns of Charmlee docents and the California Native Plant Society to Malibu City Manager Harry Peacock. “What I would hope to see,” says Witter, “is careful pre- and post-fire monitoring to determine the effects of crushing and bulldozing practices. There is a lot we don’t know yet about the effects of it, and until we do, I think monitoring is imperative. There is plenty of evidence to suggest that it might be prudent to halt the use of the crusher inside the park to allow a period of re-examination and more intensive study in order to assure that Charmlee’s precious resources are being adequately protected.