Wednesday, September 2, 2009


As the station fire continues to rage in the Angeles National Forest, I can't help mourning some of my favorite hiking and camping spots. Indeed, some of the family-friendly places mentioned on this blog have either burned or are likely to burn. 

But fire is a natural part of the forest's dominant ecosystem, chaparral. Chaparral consists of large evergreen shrubs such as ceanothus (above), chamise, manzanita, mountain mahogany, and laurel sumac. It often intergrades with sage scrub habitat, characterized by summer deciduous plants such as sages.  

Chaparral shrubs can regenerate after fires. Some resprout from burls or root crowns under the soil, others have seeds that are capable of lying dormant for a century until fire stimulates them to germinate. It's remarkable considering chaparral fires frequently reach temperatures of more than a thousand degrees. "Making them among the hottest fires in any natural environment in the world today," according to Philip Rundel and Robert Gustafson, authors of Introduction to the Plant Life of Southern California.  

"This system is a fire-prone ecosystem," Rick Halsey told KPCC listeners this week on a segment of "AirTalk" I produced.  "Its natural fire return interval is every 50-50 years, so these big fires are natural to the landscape. Not the frequency, because most of these fires are caused by humans. But the size and intensity are perfectly normal. So instead of looking at this thing as a tragedy that could have been prevented, and trying to manipulate the landscape, what we need to do is create communities that are adapted to the landscape rather than forcing the landscape to adapt to us.”  

Halsey leads California Chaparral Institute. The problem, according to Halsey and other fire ecologists, will come if people ignite another fire in the area before the native plants have time to recover. "The trick now is to keep fire out of this fire scar for at least 30 years or so," he said. "At that point the plants and the system are capable of recovering properly. The scary part of this now is often a few years after a fire, weeds get into the area, especially in wind-driven events and you can re-burn areas that already burned only 4 years before. For example the Witch fire in '07 in San Diego County burned 70,000 acres that burned 3 years before." The end result of frequent fires is a diverse landscape native shrubs are replaced by a sea of a few invasive plants, such as non-native annual grasses. 

To learn more about the problem of frequent fires, read my magazine story from last fall called Sparking the Fires

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