Hugh Safford, ecologist for the U.S. Forest Service Pacific Southwest region, said wind-driven fires roar through young chaparral and old chaparral alike. While older vegetation has more dead wood to intensify the flames, it matters only when the vegetation is adjacent to homes.
"Under Santa Ana wind conditions, it doesn't matter how old it is," he said. "Re-burns in 3-year-old chaparral are common, and some of these fires even burned through 1-year-old chaparral."
Jon Keeley, a fire ecologist for the U.S. Geological Survey, suspects the pre-human wildfires were huge -- but happened only once a century in any given area. The likely mechanism: Lightning during a monsoonal August storm started a fire in the high mountains that smoldered for months; the Santa Anas picked it up in October or November and drove it all the way to the coast.
Because native Americans didn't arrive in California until about 10,000 years ago, and evolution takes much more time than 10 millenniums to do anything worthwhile, this model is what the plants adapted to.
What the plants did not have time to adapt to, Keeley said, is fire every 10 or 20 years, as has been happening in recent times. The chaparral and coastal sage scrub -- a related plant community with many of the same species -- aren't growing back in areas that are burning frequently, letting the weeds take over.
"It's a real paradox," said Keeley. "You have these species that are absolutely fire-dependent. But the one thing wiping them out is fire."
This has been Rick Halsey's crusade of late.
The San Diego County Board of Supervisors is debating whether to start burning vast swaths of the backcountry. This basin with the senile manzanita would be a prime candidate.
"I want people to look at this and say with a straight face, 'This is trash,' " Halsey said, opening his arms to a plateau of manzanita, yucca, ceanothus.
He said these old stands are the ones the grizzly bear on our state flag loved, with a canopy high enough that the bears could lumber through corridors looking for food.
Halsey has been working with county staff, trying to change the fuel management plan they're proposing.
"One, it's not going to work," he said. "Two, it's a waste of taxpayer money. Three, it's not science-based. It's just political expediency."
Halsey is all for targeted brush thinning and clearance near homes and even favors strategic prescribed burns of old-growth chaparral near communities.
But burning the backcountry over and over is going to deal the fatal blow to the natural ecosystem.
"You wouldn't go remove the redwoods," he said. "That's what they're doing here."
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joe.mozingo@latimes.com
